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Fulltext Determinants of shisha use among secondary school students in Sudan

Othman M, Aghamohammadi N, Nik Farid ND

BMC Public Health, 2019 Oct 28;19(1):1390.
PMID: 31660934 DOI: 10.1186/s12889-019-7748-3

BACKGROUND: Shisha smoking has re-emerged in the Middle East in the last two decades and has spread rapidly in these communities. Information about shisha smoking in adolescents in Sudan is deficient. Hence, the aim of this study is to estimate the prevalence of shisha smoking among adolescents and determine the associated factors.
METHODS: This study is a school based cross sectional study among secondary school students in Khartoum State - Sudan that targets both male and female students aged 14-17 years. A total of 3387 students from 29 public and private schools were selected by multi stage random sampling. The participants completed an anonymous self-administered questionnaire which was based on Arabic version of the Global Youth Tobacco Survey (GYTS).
RESULTS: The response rate was 100% in schools and among participants, 57.3% were females and 51.6% were from public schools. The overall prevalence of those who had ever smoked shisha was 13.4%, and among male students the prevalence was 16.8%, while it was 10.9% in females. The associated factors were poor academic performance OR 2.90 CI 95% (1.21-6.94), friends smoking shisha OR 2.39 CI 95% (1.65-3.45), friends smoking cigarettes OR 2.76 CI 95% (1.90-4.01), peer pressure to smoke shisha OR 13.76 CI 95% (7.86-24.07) and unexpectedly restriction of selling shisha to minors OR 2.21 CI 95% (1.28-3.82).
CONCLUSION: The prevalence of those who had ever smoked shisha is among the lowest in Middle East region; therefore, regular surveillance system is needed. A well-structured peer based comprehensive tobacco control programmes that are supported by strict and rigorous anti-tobacco regulations which control both commercial and social resources of tobacco are needed to contain this issue among adolescents.
Isolations of enteric pathogens from synanthropic flies trapped in downtown Kuala Lumpur

Sulaiman S, Othman MZ, Aziz AH

J Vector Ecol, 2000 Jun;25(1):90-3.
PMID: 10925800

Four species of synanthropic flies were trapped in downtown Kuala Lumpur: Chrysomya megacephala, Chrysomya rufifacies, Musca domestica, and Musca sorbens. Burkholderia pseudomallei, the organism causing melioidosis, was the dominant bacteria isolated from Chrysomya megacephala. Klebsiella oxytoca, commonly associated with nosocomial infections, was commonly isolated from Chrysomya megacephala, Musca domestica, and Musca sorbens. Aeromonas hydrophila, the bacteria causing gastroenteritis, was predominantly isolated from Chrysomya megacephala and also from Musca domestica and Musca sorbens. A total of 18 bacterial species was isolated from the synanthropic flies trapped. Burkholderia pseudomallei had been reported for the first time.
Fulltext Scleroderma secondary to silica exposure--a case report

Anandan S, Othman M, Cheong I, Chin GL

Singapore Med J, 1995 Oct;36(5):559-61.
PMID: 8882549

In recent years there have been many reports of connective tissue diseases especially scleroderma following exposure to silica and silicone. We report a 51-year-old Chinese who developed a scleroderma-like disease and pulmonary silicosis eight years after exposure to silica. To our knowledge, this is the first case to be reported in Malaysia.
Fulltext A new hybrid fuzzy time series model with an application to predict PM10 concentration

Alyousifi Y, Othman M, Husin A, Rathnayake U

Ecotoxicol Environ Saf, 2021 Dec 20;227:112875.
PMID: 34717219 DOI: 10.1016/j.ecoenv.2021.112875

Fuzzy time series (FTS) forecasting models show a great performance in predicting time series, such as air pollution time series. However, they have caused major issues by utilizing random partitioning of the universe of discourse and ignoring repeated fuzzy sets. In this study, a novel hybrid forecasting model by integrating fuzzy time series to Markov chain and C-Means clustering techniques with an optimal number of clusters is presented. This hybridization contributes to generating effective lengths of intervals and thus, improving the model accuracy. The proposed model was verified and validated with real time series data sets, which are the benchmark data of actual trading of Taiwan Stock Exchange Capitalization Weighted Stock Index (TAIEX) and PM10 concentration data from Melaka, Malaysia. In addition, a comparison was made with some existing fuzzy time series models. Furthermore, the mean absolute percentage error, mean squared error and Theil's U statistic were calculated as evaluation criteria to illustrate the performance of the proposed model. The empirical analysis shows that the proposed model handles the time series data sets more efficiently and provides better overall forecasting results than existing FTS models. The results prove that the proposed model has greatly improved the prediction accuracy, for which it outperforms several fuzzy time series models. Therefore, it can be concluded that the proposed model is a better option for forecasting air pollution parameters and any kind of random parameters.
The determination of water quality and metal concentrations of Ampang Hilir Lake, Selangor, Peninsular Malaysia

Said KS, Shuhaimi-Othman M, Ahmad AK

Pak J Biol Sci, 2012 May 01;15(9):437-47.
PMID: 24163953

A study of water quality parameters (temperature, conductivity, total dissolved solid, dissolved oxygen, pH and water hardness) in Ampang Hilir Lake was conducted in January, April, July and October 2010. The water quality parameters were tested and recorded at different sampling stations chosen randomly using Hydrolab Data Sonde 4 and Surveyor 4 a water quality multi probe (USA). Six metals which were cadmium, chromium, lead, nickel, zinc and copper were determined in five different compartments of the lake namely water, total suspended solids, plankton, sediment and fish. The metals concentration were determined by Inductively Coupled Plasma Mass Spectrometer (ICP-MS), Perkin Elmer Elan, model 9000.The water quality parameters were compared with National Water Quality Standard (NWQS Malaysia) while metal concentrations were compared with Malaysian and international standards. The study shows that water quality parameters are of class 2. This condition is suitable for recreational activities where body contact is allowed and suitable for sensitive fishing activities. Furthermore, metal concentrations were found to be lower than the international standards, therefore toxic effects for these metals would be rarely observed and the adverse effects to aquatic organisms would not frequently occur.
Use of the Multispecies Freshwater Biomonitor to assess behavioral changes of Poecilia reticulata (Cyprinodontiformes: Poeciliidae) and Macrobrachium lanchesteri (Decapoda: Palaemonidae) in response to acid mine drainage: laboratory exposure

Mohti A, Shuhaimi-Othman M, Gerhardt A

J Environ Monit, 2012 Sep;14(9):2505-11.
PMID: 22868673 DOI: 10.1039/c2em10902f

The behavioral responses of guppy Poecilia reticulata (Poeciliidae) and prawn Macrobrachium lanchesteri (Palaemonidae) individuals exposed to acid mine drainage (AMD) were monitored online in the laboratory with a Multispecies Freshwater Biomonitor™ (MFB). These responses were compared to those to reference water acidified to the respective pH values (ACID). Test animals in the juvenile stage were used for both species and were exposed to AMD and ACID for 24 hours. The stress behaviors of both test animals consisted mainly of decreased activity in AMD and increased activity in ACID, indicating that the metals in the AMD played a role as a stress factor in addition to pH. The locomotor activity levels of guppies and prawns for the ACID treatment were higher than the locomotor activity levels for the AMD treatment with increasing pH value. For guppies, significant differences were observed when specimens were exposed to AMD and ACID at pH 5.0 and 6.0; the percentage activities were only 16% and 12%, respectively, for AMD treatment, whereas for ACID treatment, the percentage activities were 35% and 40%, respectively, similar to the value of 36% for the controls. Similar trends were also observed for prawns, for which the percentage activities were only 6% and 4%, respectively, for AMD treatment, whereas for ACID treatment, the percentage activities were 31% and 38%, respectively, compared to 44% in the controls. This study showed that both species are suitable for use as indicators for ecotoxicity testing with the MFB.
Fulltext Evaluation of trace metal levels in tissues of two commercial fish species in Kapar and Mersing coastal waters, Peninsular Malaysia

Bashir FA, Shuhaimi-Othman M, Mazlan AG

J Environ Public Health, 2012;2012:352309.
PMID: 22046193 DOI: 10.1155/2012/352309

This study is focused on evaluating the trace metal levels in water and tissues of two commercial fish species Arius thalassinus and Pennahia anea that were collected from Kapar and Mersing coastal waters. The concentrations of Fe, Zn, Al, As, Cd and Pb in these coastal waters and muscle, liver and gills tissues of the fishes were quantified. The relationship among the metal concentrations and the height and weight of the two species were also examined. Generally, the iron has the highest concentrations in both water and the fish species. However, Cd in both coastal waters showed high levels exceeding the international standards. The metal level concentration in the sample fishes are in the descending order livers > gills > muscles. A positive association between the trace metal concentrations and weight and length of the sample fishes was investigated. Fortunately the level of these metal concentrations in fish has not exceeded the permitted level of Malaysian and international standards.
The evaluation of water quality and metal concentrations of Titiwangsa Lake, Selangor, Peninsular Malaysia

Said KS, Shuhaimi-Othman M, Ahmad AK

Pak J Biol Sci, 2012 May 15;15(10):459-68.
PMID: 24187900

A study of water quality parameters (temperature, conductivity, total dissolved solid, dissolved oxygen, pH and water hardness) in Titiwangsa Lake was conducted in January, April, July and October 2010. The water quality parameters were tested and recorded at different sampling stations chosen randomly using hydrolab data sonde 4 and surveyor 4 a water quality multi probe (USA). Six metals i.e., cadmium, chromium, lead, nickel, zinc and copper were determined in five different compartments of the lake namely water, total suspended solids, plankton, sediment and fish. The metals concentration were determined by Inductively Coupled Plasma Mass Spectrometer (ICP-MS), perkin elmer elan, model 9000. The water quality parameters were compared with National Water Quality Standard (NWQS Malaysia) while metal concentrations were compared with Malaysian and international standards. The study shows that water quality parameters are of class 2. This condition is suitable for recreational activities where body contact is allowed and suitable for sensitive fishing activities. Furthermore, metal concentrations were found to be lower than the international standards, therefore toxic effects for these metals would be rarely observed and the adverse effects to aquatic organisms would not frequently occur.
Fulltext Deriving freshwater quality criteria for iron, lead, nickel, and zinc for protection of aquatic life in Malaysia

Shuhaimi-Othman M, Nadzifah Y, Nur-Amalina R, Umirah NS

ScientificWorldJournal, 2012;2012:861576.
PMID: 22919358 DOI: 10.1100/2012/861576

Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC(50) values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L(-1) and 9.0, 2.0, 19.9, and 36.7 μg L(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC(50) values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively.
Deriving freshwater quality criteria for copper, cadmium, aluminum and manganese for protection of aquatic life in Malaysia

Shuhaimi-Othman M, Nadzifah Y, Nur-Amalina R, Umirah NS

Chemosphere, 2013 Mar;90(11):2631-6.
PMID: 23246727 DOI: 10.1016/j.chemosphere.2012.11.030

Freshwater quality criteria for copper (Cu), cadmium (Cd), aluminum (Al), and manganese (Mn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia, which were Macrobrachiumlanchesteri (prawn), two fish -Poeciliareticulata and Rasborasumatrana, Melanoidestuberculata (snail), Stenocyprismajor (ostracod), Chironomusjavanus (midge larvae), Naiselinguis (annelid), and Duttaphrynusmelanostictus (tadpole), to determine 96-h LC50 values for Cu, Cd, Al, and Mn. The final acute values (FAVs) for Cu, Cd, Al, and Mn were 2.5, 3.0, 977.8, and 78.3 μgL(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a Criterion Maximum Concentration (CMC) and a criterion Continuous Concentration (CCC) for Cu, Cd, Al, and Mn of 1.3, 1.5, 488.9, and 39.1 μgL(-1) and 0.3, 0.36, 117.8, and 9.4 μgL(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Cu, Cd, Al, and Mn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that R.sumatrana, M.lanchesteri, C.javanus, and N.elinguis were the most sensitive to Cu, Cd, Al, and Mn, respectively.
Reduced metals concentrations of water, sediment and hyalella azteca from lakes in the vicinity of the sudbury metal smelters, Ontario, Canada

Shuhaimi-Othman M, Pascoe D, Borgmann U, Norwood WP

Environ Monit Assess, 2006 Jun;117(1-3):27-44.
PMID: 16917696

Hyalella azteca (Crustacea: Amphipoda), water and sediments from 12 circum-neutral lakes between Sudbury and North Bay in Ontario, Canada were sampled in August 1998 and analyzed for 10 metals including Cu, Zn, Cd, Ni, Pb, Co, Mo, V, Ba and Ti. Statistical analyses showed that concentrations of the metals in H. azteca, water and sediment differed significantly (ANOVA, P<0.05) among lakes (except for Zn and Pb in H. azteca and Mo in water). There was a trend of declining metal concentration, especially for Cu, Ni and Co (in water, Hyalella and sediment), with distance from the smelters indicating the reduced impact of atmospheric pollution. Metal concentrations of lakes (water) in the Sudbury area were found to be lower compared to data from the 1970s and 1980s indicating an improvement in water quality. Metal concentrations in field-collected amphipods compared favorably with those measured in the laboratory in animals exposed to deep-water sediments, provided metal concentrations were not extremely low (e.g., Pb) and that water chemistry differences (e.g., pH) were taken into account for some metals (especially Cd). In general bioaccumulation of metals in H. azteca was predicted better from surface water than from sediment total metal.
Water quality changes in Chini Lake, Pahang, West Malaysia

Shuhaimi-Othman M, Lim EC, Mushrifah I

Environ Monit Assess, 2007 Aug;131(1-3):279-92.
PMID: 17171269

A study of the water quality changes of Chini Lake was conducted for 12 months, which began in May 2004 and ended in April 2005. Fifteen sampling stations were selected representing the open water body in the lake. A total of 14 water quality parameters were measured and Malaysian Department of Environment Water Quality Index (DOE-WQI) was calculated and classified according to the Interim National Water Quality Standard, Malaysia (INWQS). The physical and chemical variables were temperature, dissolved oxygen (DO), conductivity, pH, total dissolved solid (TDS), turbidity, chlorophyll-a, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), ammonia-N, nitrate, phosphate and sulphate. Results show that base on Malaysian WQI, the water in Chini Lake is classified as class II, which is suitable for recreational activities and allows body contact. With respect to the Interim National Water Quality Standard (INWQS), temperature was within the normal range, conductivity, TSS, nitrate, sulphate and TDS are categorized under class I. Parameters for DO, pH, turbidity, BOD, COD and ammonia-N are categorized under class II. Comparison with eutrophic status indicates that chlorophyll-a concentration in the lake was in mesotrophic condition. In general water quality in Chini Lake varied temporally and spatially, and the most affected water quality parameters were TSS, turbidity, chlorophyll-a, sulphate, DO, ammonia-N, pH and conductivity.
Trend in metals variation in Tasik Chini, Pahang, Peninsular Malaysia

Shuhaimi-Othman M, Mushrifah I, Lim EC, Ahmad A

Environ Monit Assess, 2008 Aug;143(1-3):345-54.
PMID: 17987397

Water from 15 sampling stations in Tasik Chini (Chini Lake), Peninsular Malaysia were sampled for 12 months from September 2004 until August 2005 and analyzed for 11 metals including iron (Fe), aluminum (Al), manganese (Mn), barium (Ba), zinc (Zn), lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), chromium (Cr) and cobalt (Co). Results showed that the mean (min-max) metal concentrations (in micrograms per liter) in Tasik Chini waters for the 12 months sampling based on 15 sampling stations (in descending order) for Fe, Al, Mn, Ba, Zn, Pb, Cu and Cd were 794.84 (309.33-1609.07), 194.53 (62.37-665.93), 29.16 (16.68-79.85), 22.07 (15.64-29.71), 5.12 (2.224-6.553), 2.36 (1.165-4.240), 0.832 (0.362-1.443) and 0.421 (0.254-0.696) respectively. Concentration for three metals i.e. Ni, Cr and Co were too low and not detected by the graphite furnace Atomic Absorption Spectrophotometry (AAS). Comparison with various water quality standards showed that the mean metals concentration in surface water of Tasik Chini were low and within the range of natural background except for Fe and Al. In general, metal concentrations in Tasik Chini water varied temporally and spatially. The main factors influencing these metal concentrations in the water were the raining season and mining activities. Stations located at Tanjung Jerangking and Melai areas were the most effected due to those factors.
Assessment of heavy metals in tilapia fish (Oreochromis niloticus) from the Langat River and Engineering Lake in Bangi, Malaysia, and evaluation of the health risk from tilapia consumption

Taweel A, Shuhaimi-Othman M, Ahmad AK

Ecotoxicol Environ Saf, 2013 Jul;93:45-51.
PMID: 23642778 DOI: 10.1016/j.ecoenv.2013.03.031

Concentrations of the heavy metals copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb) and nickel (Ni) were determined in the liver, gills and muscles of tilapia fish from the Langat River and Engineering Lake, Bangi, Selangor, Malaysia. There were differences in the concentrations of the studied heavy metals between different organs and between sites. In the liver samples, Cu>Zn>Ni>Pb>Cd, and in the gills and muscle, Zn>Ni>Cu>Pb>Cd. Levels of Cu, Cd, Zn and Pb in the liver samples from Engineering Lake were higher than in those from the Langat River, whereas the Ni levels in the liver samples from the Langat River were greater than in those from Engineering Lake. Cd levels in the fish muscle from Engineering Lake were lower than in that from the Langat River. Meanwhile, the Cd, Zn and Pb levels in the fish muscle from the Langat River were lower than in that from Engineering Lake, and the Ni levels were almost the same in the fish muscle samples from the two sites. The health risks associated with Cu, Cd, Zn, Pb and Ni were assessed based on the target hazard quotients. In the Langat River, the risk from Cu is minimal compared to the other studied elements, and the concentrations of Pb and Ni were determined to pose the greatest risk. The maximum allowable fish consumption rates (kg/d) based on Cu in Engineering Lake and the Langat River were 2.27 and 1.51 in December and 2.53 and 1.75 in February, respectively. The Cu concentrations resulted in the highest maximum allowable fish consumption rates compared with the other studied heavy metals, whereas those based on Pb were the lowest. A health risk analysis of the heavy metals measured in the fish muscle samples indicated that the fish can be classified at one of the safest levels for the general population and that there are no possible risks pertaining to tilapia fish consumption.
Connecting salt stress signalling pathways with salinity-induced changes in mitochondrial metabolic processes in C3 plants

Che-Othman MH, Millar AH, Taylor NL

Plant Cell Environ, 2017 Dec;40(12):2875-2905.
PMID: 28741669 DOI: 10.1111/pce.13034

Salinity exerts a severe detrimental effect on crop yields globally. Growth of plants in saline soils results in physiological stress, which disrupts the essential biochemical processes of respiration, photosynthesis, and transpiration. Understanding the molecular responses of plants exposed to salinity stress can inform future strategies to reduce agricultural losses due to salinity; however, it is imperative that signalling and functional response processes are connected to tailor these strategies. Previous research has revealed the important role that plant mitochondria play in the salinity response of plants. Review of this literature shows that 2 biochemical processes required for respiratory function are affected under salinity stress: the tricarboxylic acid cycle and the transport of metabolites across the inner mitochondrial membrane. However, the mechanisms by which components of these processes are affected or react to salinity stress are still far from understood. Here, we examine recent findings on the signal transduction pathways that lead to adaptive responses of plants to salinity and discuss how they can be involved in and be affected by modulation of the machinery of energy metabolism with attention to the role of the tricarboxylic acid cycle enzymes and mitochondrial membrane transporters in this process.
Fulltext Extractive Fermentation of Lactic Acid in Lactic Acid Bacteria Cultivation: A Review

Othman M, Ariff AB, Rios-Solis L, Halim M

Front Microbiol, 2017;8:2285.
PMID: 29209295 DOI: 10.3389/fmicb.2017.02285

Lactic acid bacteria are industrially important microorganisms recognized for their fermentative ability mostly in their probiotic benefits as well as lactic acid production for various applications. Nevertheless, lactic acid fermentation often suffers end-product inhibition which decreases the cell growth rate. The inhibition of lactic acid is due to the solubility of the undissociated lactic acid within the cytoplasmic membrane and insolubility of dissociated lactate, which causes acidification of cytoplasm and failure of proton motive forces. This phenomenon influences the transmembrane pH gradient and decreases the amount of energy available for cell growth. In general, the restriction imposed by lactic acid on its fermentation can be avoided by extractive fermentation techniques, which can also be exploited for product recovery.
Fulltext Strategies for improving production performance of probiotic Pediococcus acidilactici viable cell by overcoming lactic acid inhibition

Othman M, Ariff AB, Wasoh H, Kapri MR, Halim M

AMB Express, 2017 Nov 27;7(1):215.
PMID: 29181600 DOI: 10.1186/s13568-017-0519-6

Lactic acid bacteria are industrially important microorganisms recognized for fermentative ability mostly in their probiotic benefits as well as lactic acid production for various applications. Fermentation conditions such as concentration of initial glucose in the culture, concentration of lactic acid accumulated in the culture, types of pH control strategy, types of aeration mode and different agitation speed had influenced the cultivation performance of batch fermentation of Pediococcus acidilactici. The maximum viable cell concentration obtained in constant fed-batch fermentation at a feeding rate of 0.015 L/h was 6.1 times higher with 1.6 times reduction in lactic acid accumulation compared to batch fermentation. Anion exchange resin, IRA 67 was found to have the highest selectivity towards lactic acid compared to other components studied. Fed-batch fermentation of P. acidilactici coupled with lactic acid removal system using IRA 67 resin showed 55.5 and 9.1 times of improvement in maximum viable cell concentration compared to fermentation without resin for batch and fed-batch mode respectively. The improvement of the P. acidilactici growth in the constant fed-batch fermentation indicated the use of minimal and simple process control equipment is an effective approach for reducing by-product inhibition. Further improvement in the cultivation performance of P. acidilactici in fed-bath fermentation with in situ addition of anion-exchange resin significantly helped to enhance the growth of P. acidilactici by reducing the inhibitory effect of lactic acid and thus increasing probiotic production.
Fulltext Totally opportunistic routing algorithm (TORA) for underwater wireless sensor network

Rahman Z, Hashim F, Rasid MFA, Othman M

PLoS One, 2018;13(6):e0197087.
PMID: 29874237 DOI: 10.1371/journal.pone.0197087

Underwater Wireless Sensor Network (UWSN) has emerged as promising networking techniques to monitor and explore oceans. Research on acoustic communication has been conducted for decades, but had focused mostly on issues related to physical layer such as high latency, low bandwidth, and high bit error. However, data gathering process is still severely limited in UWSN due to channel impairment. One way to improve data collection in UWSN is the design of routing protocol. Opportunistic Routing (OR) is an emerging technique that has the ability to improve the performance of wireless network, notably acoustic network. In this paper, we propose an anycast, geographical and totally opportunistic routing algorithm for UWSN, called TORA. Our proposed scheme is designed to avoid horizontal transmission, reduce end to end delay, overcome the problem of void nodes and maximize throughput and energy efficiency. We use TOA (Time of Arrival) and range based equation to localize nodes recursively within a network. Once nodes are localized, their location coordinates and residual energy are used as a matrix to select the best available forwarder. All data packets may or may not be acknowledged based on the status of sender and receiver. Thus, the number of acknowledgments for a particular data packet may vary from zero to 2-hop. Extensive simulations were performed to evaluate the performance of the proposed scheme for high network traffic load under very sparse and very dense network scenarios. Simulation results show that TORA significantly improves the network performance when compared to some relevant existing routing protocols, such as VBF, HHVBF, VAPR, and H2DAB, for energy consumption, packet delivery ratio, average end-to-end delay, average hop-count and propagation deviation factor. TORA reduces energy consumption by an average of 35% of VBF, 40% of HH-VBF, 15% of VAPR, and 29% of H2DAB, whereas the packet delivery ratio has been improved by an average of 43% of VBF, 26% of HH-VBF, 15% of VAPR, and 25% of H2DAB. Moreover, the average end-to-end delay has been reduced by 70% of VBF, 69% of HH-VBF, 46% of VAPR, and 73% of H2DAB. Furthermore, average hope-count has been improved by 57%, 53%, 16% and 31% as compared to VBF, HHVBF, VAPR, and H2DAB, respectively. Also, propagation delay has been reduced by 34%, 30%, 15% and 23% as compared to VBF, HHVBF, VAPR, and H2DAB, respectively.
Fulltext A Midgut Digestive Phospholipase A2 in Larval Mosquitoes, Aedes albopictus and Culex quinquefasciatus

Abdul Rahim NA, Othman M, Sabri M, Stanley DW

Enzyme Res, 2018;2018:9703413.
PMID: 29862070 DOI: 10.1155/2018/9703413

Phospholipase A2 (PLA2) is a secretory digestive enzyme that hydrolyzes ester bond at sn-2 position of dietary phospholipids, creating free fatty acid and lysophospholipid. The free fatty acids (arachidonic acid) are absorbed into midgut cells. Aedes albopictus and Culex quinquefasciatus digestive PLA2 was characterized using a microplate PLA2 assay. The enzyme showed substantial activities at 6 and 8 μg/μl of protein concentration with optimal activity at 20 and 25 μg/μl of substrate concentration in Aedes albopictus and Culex quinquefasciatus, respectively. PLA2 activity from both mosquitoes increased in a linear function up to 1 hour of the reaction time. Both enzymes were sensitive to pH and temperature. PLA2 showed higher enzyme activities in pH 8.0 and pH 9.0 from Aedes albopictus and Culex quinquefasciatus, respectively, at 40°C of incubation. The PLA2 activity decreased in the presence of 5 mM (Aedes albopictus) and 0.5 mM (Culex quinquefasciatus) site specific PLA2 inhibitor, oleyloxyethylphosphorylcholine. Based on the migration pattern of the partially purified PLA2 on SDS-PAGE, the protein mass of PLA2 is approximately 20-25 kDa for both mosquitoes. The information on PLA2 properties derived from this study may facilitate in devising mosquitoes control strategies especially in the development of inhibitors targeting the enzyme active site.
Wheat mitochondrial respiration shifts from the tricarboxylic acid cycle to the GABA shunt under salt stress

Che-Othman MH, Jacoby RP, Millar AH, Taylor NL

New Phytol, 2020 02;225(3):1166-1180.
PMID: 30688365 DOI: 10.1111/nph.15713

Mitochondrial respiration and tricarboxylic acid (TCA) cycle activity are required during salt stress in plants to provide ATP and reductants for adaptive processes such as ion exclusion, compatible solute synthesis and reactive oxygen species (ROS) detoxification. However, there is a poor mechanistic understanding of how salinity affects mitochondrial metabolism, particularly respiratory substrate source. To determine the mechanism of respiratory changes under salt stress in wheat leaves, we conducted an integrated analysis of metabolite content, respiratory rate and targeted protein abundance measurements. Also, we investigated the direct effect of salt on mitochondrial enzyme activities. Salt-treated wheat leaves exhibit higher respiration rate and extensive metabolite changes. The activity of the TCA cycle enzymes pyruvate dehydrogenase complex and the 2-oxoglutarate dehydrogenase complex were shown to be directly salt-sensitive. Multiple lines of evidence showed that the γ-aminobutyric acid (GABA) shunt was activated under salt treatment. During salt exposure, key metabolic enzymes required for the cyclic operation of the TCA cycle are physiochemically inhibited by salt. This inhibition is overcome by increased GABA shunt activity, which provides an alternative carbon source for mitochondria that bypasses salt-sensitive enzymes, to facilitate the increased respiration of wheat leaves.

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