CF-LIBS based elemental analysis of Saussurea simpsoniana medicinal plant: a study on roots, seeds, and leaves

The plant Saussurea Simpsoniana, which has been used in traditional medicine for its biocompatibility and abundant nutrients, offers a wide range of remedies. Local communities effectively utilize medicines derived from the plant's roots to treat various ailments such as bronchitis, rheumatic pain, and abdominal and nervous disorders. In this study, we present an elemental analysis of the chemical composition (wt%) of this medicinal plant using the laser-induced breakdown spectroscopy (LIBS) technique. In the air atmosphere, an Nd:YAG (Q-switched) laser operating at a wavelength of 532 nm is utilized to create plasma on the sample's surface. This laser has a maximum pulse energy of approximately 400 mJ and a pulse duration of 5 ns. A set of six miniature spectrometers, covering the wavelength range of 220-970 nm, was utilized to capture and record the optical emissions emitted by the plasma. The qualitative analysis of LIBS revealed the presence of 13 major and minor elements, including Al, Ba, C, Ca, Fe, H, K, Li, Mg, Na, Si, Sr, and Ti. Quantitative analysis was performed using calibration-free laser-induced breakdown spectroscopy (CF-LIBS), ensuring local thermodynamical equilibrium (LTE) and optically thin plasma condition by considering plasma excitation temperature and electron number density. In addition, a comparison was made between the results obtained from CF-LIBS and those acquired through energy-dispersive X-ray spectroscopy (EDX) analysis.

Synthesis of Carbon Nanotubes (CNTs) from Poultry Litter for Removal of Chromium (Cr (VI)) from Wastewater

Pakistan, an agricultural country, raises 146.5 million commercial and domestic poultry birds, which generate around 544,831 tons of waste per year. This waste finds its final disposal in agricultural land as soil fertilizer or disposal site amendment. The usage of poultry litter for this purpose is uncontrolled, which results in environmental degradation such as emission of greenhouse gases, e.g., methane. However, alternative options such as thermochemical conversion of poultry litter can offer better solutions where this waste can be used as a low-cost carbon source for the synthesis of Multiwalled Carbon Nanotubes (MWCNTs). In this study, efforts were made to utilize this cheap and plentiful carbon source for the synthesis of CNTs in the presence of Ni/Mo/MgO as a catalyst, through pyrolysis. For a better yield of carbon product, the optimum ratio for the catalysts (Ni/Mo/MgO) was found to be 4:0.2:1. Furthermore, the process parameters were also optimized for better carbon yield. A good yield of CNTs resulted from a pyrolysis time of 12 min, a temperature of 825 °C, and a catalyst weight of 100 mg. The structure and morphology of the produced nanotubes were confirmed through X-ray Diffractometer (X-RD) and Scanning Electron Microscopy (SEM). The environmental application of the nanotubes was tested in a synthetic chromium solution in the lab using a batch experiment. Different experimental conditions (pH, adsorbent dosage, and contact time) were optimized to improve the adsorption of Cr (VI) by carbon nanotubes and a UV-Visible spectrophotometer was used at 540 nm to measure the absorbance of Cr (VI). The results showed that up to 81.83% of Cr (VI) removal was achieved by using 8 mg of CNTs at pH 3 with 400 rpm at 180 min of contact time. Thus, it was concluded that poultry litter can be a useful source for the synthesis of MWCNTs and thereby removal of Cr (VI) from industrial tanneries' wastewater.

Phytoaccumulation of heavy metals from municipal solid waste leachate using different grasses under hydroponic condition

Grasses have been used widely to remediate contaminants present in domestic wastewater, but leachate generated from municipal solid waste that usually contain some concentrations of heavy metals has never been reported to be treated with grasses, especially Rhodes grass. A series of experiments was performed to investigate the contaminant uptake from municipal solid waste leachate by Chloris gayana (Rhodes grass) grown in combination with two commonly available grass varieties namely Vetiveria zizanioides (Vetiver grass) and Pennisetum purpureum (Elephant grass). Leachate used for the experiments had high values for chemical oxygen demand (5 g/L), pH (8.5), electrical conductivity (9.0 mS/cm), nitrates (182.1 mg/L), phosphates 6.4 mg/L along with heavy metals i.e. copper, zinc and manganese. Different dilutions of leachate ranging from 0 to 100% were applied in batches and their result showed that collectively all the grasses reduced overall contaminant concentrations. These were reported for chemical oxygen demand, electrical conductivity, nitrates, and phosphates reduced up to 67, 94, 94, and 73%, respectively. Metals uptake by grasses also showed a significant decrease in applied dose i.e. zinc (97%), copper (89%), and manganese (89%). Plant analysis showed that all grasses showed preference to heavy metals uptake e.g. Rhodes grass favoured up taking zinc, Elephant grass for copper and Vetiver grass preferred manganese. Overall growth performance of Rhodes grass was better in dilute leachate, whereas in more concentrated leachate, Rhodes grass did not perform better and production of biomass decreased. In Vetiver grass, root and shoot lengths decreased with increasing leachate strength, but the biomass did not change significantly.

Growth and nutrient removal efficiency of duckweed (lemna minor) from synthetic and dumpsite leachate under artificial and natural conditions

Sustainable management of leachate produced from the dumpsite is one of the major concerns in developing countries Aquatic plants such as duckweed have the potential to remove pollutants from wastewater which can also be cost-effective and feasible options for leachate treatment. Therefore, the objective of our present study was to examine the growth and nutrient removal efficiency of duckweed (Lemna minor) on leachate. Three tests were performed each by growing lemna minor on synthetic leachate under controlled conditions and on dumpsite leachate under natural conditions. During each test, duckweed was grown in 300 ml plastic containers with a surface area of 25.8 cm2. About 60 mg of fresh mass of duckweed was grown on 250 ml leachate at an internal depth of 9.5 cm. Results revealed that, in comparison to synthetic leachate, duckweed removed Chemical Oxygen Demand (COD), nitrogen (N), and phosphorous (P) more efficiently from dumpsite leachate under natural climatic conditions. However, the amounts of N and P absorbed into duckweed body mass were about 16% and 35% respectively more at synthetic leachate under controlled conditions. Maximum growth rate of duckweed (7.03 g m-2 day-1) was also observed for synthetic leachate in comparison to the growth rate of 4.87 g m-2 day-1 at dumpsite leachate. Results of this study provide a useful interpretation of duckweed growth and nutrient removal dynamics from leachate under natural and laboratory conditions.

Assessing the generation, recycling and disposal practices of electronic/electrical-waste (E-Waste) from major cities in Pakistan

Rapid increase in the quantity of electronic/electrical-waste (e-waste) has become an emerging issue throughout the world. To avoid higher expenditures on safe disposal and recycling, large quantities of e-waste are being exported from developed to developing countries like Pakistan. Emerging issue of e-waste in Pakistan demands its effective management strategy for the country. However, it cannot be achieved until assessment of e-waste quantification and disposal is carried out. The main objective of this study was to quantify the e-waste inventory and it's processing from major cities of Pakistan to evaluate its generation (domestic/import) and recycling practices. This study comprises the information of only those e-waste items (desktop computers, laptops/notebooks, computer monitors and liquid-crystal display units) which form the major portion of e-waste imported to Pakistan. Survey based data collected from three major cities/areas have been extrapolated to develop an e-waste generation inventory for the country. The study reveals that approximately 50 kt of e-waste is being imported as scrap in addition to its local generation of about 38 kt per year. During field visits and data collection surveys, it has been observed that the processing of e-waste in the country is being carried out in crude manner without safety gears. Findings of our study strongly recommend dire need for urgent and effective monitoring as well as control of informal e-waste management in Pakistan.

Multiplex real-time RT-PCR assay for transfusion transmitted viruses in sero-negative allogeneic blood donors: an experience from Southern Pakistan

BACKGROUND

Blood transfusion safety commences with healthy donor recruitment. The threat of transfusion transmitted infections is greatly minimized by serological tools but not entirely eliminated. Recently, nucleic-acid testing for blood donor screening has virtually eliminated this jeopardy.

METHODS

This prospective study was conducted from February 2015 to February 2016. Samples from seronegative donors were run on multiplex assay (Cobas, S-201 system platform, Roche) in a batch of six [MP-NAT]. In case of reactive pool, tests were run on every individual sample [IDNAT].

RESULTS

Of 16957 donors, 16836 (99.2%) were replacement donors and the remaining 121 (0.7%) were voluntary donors, with a mean age of 29.09 ± 7.04 years. After serologic screening of all 16957 donors, 955 (5.6%) were found to be reactive; 291(1.71%) were reactive for hepatitis-B surface antigen, 361 (2.12%) for antibody to hepatitis C virus (anti-HCV), 14 (0.08%) for antibody to human immunodeficiency virus, 287 (1.69%) for syphilis and 2 (0.01%) for malaria. 14 (0.08%) NAT reactive donors were identified after testing the 16002 seronegative donors, with an overall NAT yield of one reactivity out of 1143 blood donations; 10 donors for HBV-DNA (HBV NAT yield-1:1600) and remaining 4 for HCV-RNA (HCV-NAT yield-1:4000). None were HIV positive.

CONCLUSION

NAT has improved the safety attributes in blood products. Although the positivity rate for NAT testing is low but in view of the high prevalence of transfusion transmitted infections in our country, we recommend the parallel use of both serology and NAT screening of all donated blood.

Effects of Pyrolysis Temperature on Product Yields and Energy Recovery from Co-Feeding of Cotton Gin Trash, Cow Manure, and Microalgae: A Simulation Study

The intensive search of new and cleaner energy catches interest in recent years due to huge consumption of fossil fuels coupled with the challenge of energy and environmental sustainability. Production of renewable and environmentally benign energy from locally available raw materials is coming in the frontline. In this work, conversion of the combined biomass (cotton gin trash, cow manure, and Microalgae [Nannochloropsis oculata]) through batch pyrolysis has been investigated. The effect of temperature to the production of energy fuels such as bio-oil, char, and biogas have been simulated considering the yield and energy content as responses. Result of the investigation generally revealed that the proportions of the different biomass did not significantly affect the product yield and energy recovery. Significant effect of temperature is evident in the simulation result of energy recovery whereby maximum conversion was achieved at 400°C for char (91 wt%), 600°C for syngas (22 wt%), and 551°C for bio-oil (48 wt%). Overall energy conversion efficiency of 75.5% was obtained at 589°C in which 15.6 MJ/kg of mixed biomass will be elevated to pyrolysis products.

Grain Size and Interface Dependence of Bias Stress Stability of n-Type Organic Field Effect Transistors

The effect of grain size and interface dependence of bias stress stability of C60-based n-type organic field effect transistors (OFETs) has been studied. It has been realized that, with increasing grain size of C60, the bias stress induced threshold voltage shift can be controlled and this effect is mainly attributed to the mechanism of charge trapping at grain boundaries. It is further studied that the growth of C60 on the surface of parylene at elevated substrate temperature leads to the creation of radicals at the interface between the active layer and the gate dielectric. These radicals help to improve the bias stress stability of C60-based n-type OFETs. For achieving the bias stress stability, we have presented a procedure of creation of radicals at the interface between C60 and parylene in single gate OFETs instead of dual gate OFETs.

Public health surveillance at a mass gathering: urs of Baba Farid, Pakpattan district, Punjab, Pakistan, December 2010

The objective of this study was to identify health related problems encountered during an annual mass gathering in Pakpattan, Pakistan, the anniversary of the death (urs) of Baba Farid, and to make recommendations for planning and prevention activities. A surveillance system was established to capture health related data for the event. A list of reportable diseases was developed. Data were collected pre-, during, and post-event by health care workers trained for the purpose. A total of 5918 people reported to the 15 health care facilities providing services during the event; 58% of consultations were because of communicable diseases, 21% of which were respiratory tract infections and 26% gastrointestinal illness. Injuries accounted for 31% of cases and noncommunicable diseases for 11%. Prevalence of reportable disease during the event showed sizeable increases. No major disease outbreak was observed.

A comparison of TiO2 nanoparticles and nanotubes for catalytic gas phase destruction of H2S gas at high temperatures

Reduction of H2S gas over Sulphur doped TiO2 nanoparticles and TiO2 nanotubes was studied in this work. Fixed bed catalytic system was used for the catalytic reduction of H2S gas at a high temperature of 450 degrees C under laboratory conditions. 99.97% reduction was achieved using S-doped TiO2. 2.89% Sulphur was adsorbed on S-doped TiO2 nanoparticles in the form of Ti(SO4)2, while 95.6% reduction was achieved in case of TiO2 nanotubes and the sulphur adsorption was 2.67%. The XRD, SEM, and EDX techniques were carried out to characterize the nanoparticles and nanotubes, while gas reduction analysis was carried out using GC-MS for gas samples.

Nanostructured materials for water desalination

Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.

On-line monitoring of remediation process of chromium polluted soil using LIBS

Due to large growth in leather and textile industries to cater for the needs of a growing world population, contamination of soil and water resources by chromium has become a great threat for humans and animals. In this work, Laser Induced Breakdown Spectroscopy (LIBS) was applied to monitor the remediation process of soil contaminated with Chromium metal. This study was conducted at a laboratory scale by setting up an experiment in a container holding soil contaminated with chromium. This setup represents actual field conditions where remediation process could be applied and monitored for the removal of toxic metals like Cr. For generation of LIBS spectrum, the plasma was produced by focusing a pulsed Nd: YAG laser at 1064 nm on the soil contaminated with chromium under remediation process. The evaluation of the potential and capabilities of LIBS as a rapid tool for remediation process of contaminated sites is discussed in detail. Optimal experimental conditions were evaluated for improving the sensitivity of our LIBS system for monitoring of remediation process through parametric dependence study. The minimum detection limit of our spectrometer for chromium in soil matrix was 2 mg Kg(-1).

Measurement of nutrients in green house soil with laser induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) has been applied for the determination of nutrients in the green house soil samples. We determined appropriate spectral signatures of vital nutrients and calibrated the method to measure the nutrients in a naturally fertilized plot, cultivated with tomato and cucumber plants. From the calibration curves we predicted the concentrations of important nutrients such as Ca, K, P, Mg, Fe, S, Ni and Ba in the soil. Our measurements proved that the LIBS method rapidly and efficiently measures soil nutrients with excellent detection limits of 12, 9, 7, 9, 7, 10, 8 and 12 mg/kg for Ca, K, P, Mg, Fe, S, Ni and Ba respectively with a precision of approximately 2%, The unique features of LIBS for rapid sample analysis demonstrated by this study suggests that this method offers promise for precision measurements of soil nutrients as compared to conventional methods in short span of time.

Intravitreal steroids may facilitate treatment of Eales' disease (idiopathic retinal vasculitis): an interventional case series

PURPOSE

Eales' disease is an idiopathic peripheral perivasculitis leading to proliferative vascular retinopathy, recurrent vitreous haemorrhages, and tractional retinal detachment. It is an elusive cause of blindness in young, otherwise healthy individuals. We studied the effects of intravitreal triamcinolone acetonide (IVTA) in patients of Eales' disease, which may eventually reduce the side effects and cost of management, with results equivalent to or better than oral steroids.

METHODS

Ethics approval and prior patient consent were obtained. Fluorescein fundus angiograms (FFAs) of 12 eyes of 12 Eales' disease patients were taken before enrolment. These patients received 0.1 ml of 40 mg/ml (4 mg) intravitreal triamcinolone through pars plana under topical anaesthesia. Regular weekly follow-ups were initiated to ascertain Snellen visual acuity, intraocular pressure (IOP) with Goldman tonometer, and triple mirror examination. Fluorescein fundus angiography was again performed in the 8th week to monitor response to treatment. Decrease in areas of late perivascular dye extravasation on fluorescein angiography was used as marker for improvement.

RESULTS

Ten out of a total of 12 (83.33%) eyes treated with IVTA showed significant reduction of late leakage from retinal vessels on fluorescein fundus angiography. Two out of 12 eyes (16.67%) did not show considerable decrease in late perivascular fluorescein dye leakage after 8 weeks of intravitreal triamcinolone injection. Two patients (16.67%) had a significant rise in IOP after IVTA.

CONCLUSION

Intravitreal steroids may be advocated for management of idiopathic retinal vasculitis without complications of systemic steroids, and minimize need for more invasive procedures.

Effect of polyols and salts on the acid-induced state of human placental cystatin

Polyols (glycerol and sorbitol) and salts (magnesium sulfate, sodium sulfate, and magnesium chloride) have been used to study the refolding of the acid-induced state of human placental cystatin (HPC), which is a low molecular weight (12,500 daltons) thiol proteinase inhibitor, in terms of CD spectroscopy, binding of hydrophobic dye 1-anilinonaphthalene-8-sulfonic acid (ANS), and intrinsic fluorescence measurements. The helical content of acid-denatured HPC increased with increase in glycerol concentration (0-80%). At 80% glycerol concentration, the secondary structural features observed in the far UV-CD region are similar to those of the native state (pH 6.0). The intrinsic fluorescence and near UV-CD studies showed that this 80% glycerol-induced state has a significant amount of tertiary structure with decreased ANS binding compared to the acid-denatured state. It was found that glycerol is more effective in stabilizing the acid-denatured state of HPC as compared to sorbitol. Among salts the stability effect was more for MgCl(2) (used up to concentration of 3 M) compared to MgSO(4) and Na(2)SO(4) (used up to the concentration of 1.5 M due to restricted solubility of HPC at higher sulfate salt concentrations) as determined by CD studies and fluorescence measurements, which showed secondary and tertiary structural resemblance of this MgCl(2)-induced state close to native state and showed overall spectral features in between the native state and the acid-denatured state. This MgCl(2) (3 M)-induced state showed decreased ANS fluorescence as compared to the acid-denatured state but more than that of the native state. The results taken together suggest that the acid-denatured state of HPC in the presence of 80% glycerol or 3 M MgCl(2) has a conformation in between that of the native state (pH 6.0) and the acid-induced state at pH 2.0.

Inducing systemic and mucosal immune responses to B-T construct of F1 antigen of Yersinia pestis in microsphere delivery

Plague is a zoonotic disease caused by Yersinia pestis, an etiological agent of pneumonic and bubonic plague. There is a need for an improved plague vaccine that may overcome the limitation of presently available whole cell vaccine. An alternative approach described here, is the use of protective epitopes from immunodominant antigen of Y. pestis. One such antigen is the F1 antigen, a major envelope and virulent protein that possess antiphagocytic and anti-microbial properties. The present study was aimed to develop a peptide-based vaccine, based upon the constructs made between B and T cell epitopes of F1 antigen of Y. pestis. The immunogenicity, IgG subclass pattern, affinity, avidity and in vivo protective efficacy of the antibodies generated for different B-T constructs were studied in murine model using microsphere as the delivery vehicle. The mode of immunization was both intranasal and intramuscular, with single and multiple doses of immunization, respectively. Intranasal immunization generated consistent high titre and long lasting immune response both for IgG and IgA in sera and sIgA in washes while intramuscular route generated peak IgG levels in sera only. The IgG isotypic levels pattern showed higher IgG2a/IgG2b levels in intranasal route while mixed isotypic levels of IgG1, IgG2a/IgG2b were observed in intramuscular route. The affinity and relative avidity of antibodies showed best results with intranasal route as compared to the intramuscular route. The specific activity measurement (IgG/IgA content) in sera and washes were well correlated with the antibody levels. Finally, in vivo protective studies showed that B1T1 and B2T1 conjugates protected the mice till day 15 while rest of the conjugates showed poor protection.

Molten globule state of human placental cystatin (HPC) at low pH conditions and the effects of trifluoroethanol (TFE) and methanol

Acid-induced conformational changes were studied in human placental cystatin (HPC) in terms of circular dichroism (CD) spectroscopy, the binding of hydrophobic dye 1-anilinonapthalene-8-sulphonic acid (ANS), and intrinsic fluorescence measurements. Our results show the formation of an acid-induced molten globule state at pH 2.0, with significant secondary and tertiary interactions that resemble the native state, exposed hydrophobic regions and the effects of trifluoroethanol (TFE) and methanol in conversion of the acid-denatured state of HPC to the alcohol-induced state, which is characterized by increased helical content, disrupted tertiary structure, and the absence of hydrophobic clusters. Alcohol-induced formation of α-helical structures at pH 2.0 is evident from the increase in the ellipticity values at 222 nm, with native-like secondary structural features at 40% TFE. The increase in helical content was observed up to 80% TFE concentration. The ability of TFE (40%) to refold acid-denatured HPC to native-state conformation is also supported by intrinsic and ANS fluorescence measurements.Key words: human placental cystatin, molten globule, acid-induced state, trifluoroethanol, methanol, CD spectroscopy, ANS fluorescence, pH, protein folding.

Simultaneous selection of the wild-type genotypes of the G894T and 4B/ 4A polymorphisms of NOS3 associate with high-altitude adaptation

The routine performance of high-altitude (HA) natives in the hypoxic environment of HA exemplifies the process of adaptation mainly through natural selection. The recent therapeutic application of nitric oxide (NO) in HA disorders, for the improvement of oxygenation and vasodilation, ushered us to investigate the endothelial nitric oxide synthase gene (NOS3) with respect to HA adaptation. The study subjects, 131 HA monks (HAM), 136 HA controls (HAC), and 170 lowlanders (LLs) were screened for NOS3 G894T (Glu298Asp) and 4B/4A polymorphisms. The NO levels were estimated, for a correlation with the polymorphisms. The three groups were in Hardy-Weinberg equilibrium for the polymorphisms. The overall genotype distributions for the G894T and 4B/4A polymorphisms were significant (P = 0.01 and 0.02, respectively) in the three groups. Wild-type alleles G and 4B were significantly over-represented in the HA groups as compared to the LLs (P = 0.006 and P = 0.02, respectively). The NO levels were in the order of HAM>HAC>LLs (P < 0.0001). Furthermore, combinations of the GG and BB genotypes were distributed significantly more frequently in the HAM (P < 0.0001) and HAC (P = 0.0005) than in LLs. The NO levels contributed by the wild-type genotype combination GG, BB were significantly elevated when compared with the remaining eight genotype combinations together in the HAM, HAC and LLs (P = 0.003, P = 0.0006 and P < 0.0001, respectively). To conclude, the genotype combination of NOS3 wild-type homozygotes (GG, BB) was found significantly more frequently in HA groups than in LLs, by contributing to higher NO levels associated with HA adaptation.

Laboratory scale studies on removal of chromium from industrial wastes

Chromium being one of the major toxic pollutants is discharged from electroplating and chrome tanning processes and is also found in the effluents of dyes, paint pigments, manufacturing units etc. Chromium exists in aqueous systems in both trivalent (Cr(3+)) and hexavalent (Cr(6+)) forms. The hexavalent form is carcinogenic and toxic to aquatic life, whereas Cr(3+) is however comparatively less toxic. This study was undertaken to investigate the total chromium removal from industrial effluents by chemical means in order to achieve the Pakistan NEQS level of 1 mg/L by the methods of reduction and precipitation. The study was conducted in four phases. In phase I, the optimum pH and cost effective reducing agent among the four popular commercial chemicals was selected. As a result, pH of 2 was found to be most suitable and sodium meta bisulfate was found to be the most cost effective reducing agent respectively. Phase II showed that lower dose of sodium meta bisulfate was sufficient to obtain 100% efficiency in reducing Cr(6+) to Cr(3+), and it was noted that reaction time had no significance in the whole process. A design curve for reduction process was established which can act as a tool for treatment of industrial effluents. Phase III studies indicated the best pH was 8.5 for precipitation of Cr(3+) to chromium hydroxide by using lime. An efficiency of 100% was achievable and a settling time of 30 minutes produced clear effluent. Finally in Phase IV actual waste samples from chrome tanning and electroplating industries, when precipitated at pH of 12 gave 100% efficiency at a settling time of 30 minutes and confined that chemical means of reduction and precipitation is a feasible and viable solution for treating chromium wastes from industries.

Differential changes in the steady state levels of thylakoid membrane proteins during senescence in Cucumis sativus cotyledons

Chloroplast structure and function is known to alter during foliar senescence. Besides, the alterations in the structural organisation of thylakoid membranes changes in the steady state levels of thylakoid membrane proteins occur due to leaf ageing. We monitored temporal changes in some of the specific proteins of thylakoid membrane protein complexes by western blotting in the Cucumis sativus cotyledons as a function of the cotyledon age. We observed that the levels of D1 and D2 proteins of photosystem II started declining at the early stages of senescence of Cucumis cotyledons and continued to decline with the progress of cotyledon age. Similarly the level of Cyt f of Cyt b6/f complex declined rapidly with progress of senescence in these cotyledons. The reaction centre proteins of photosystem I were relatively found to be more stable than that of photosystem II reaction centre proteins reflecting possibly the disorganisation of photosystem II prior to photosystem I. The 33 kDa extrinsic protein (MSP) of oxygen evolving complex, the LHCII apoprotein and the beta-subunit of ATPsynthase showed the declined levels with the progress of cotyledon age. However, the extents of loss of these proteins were not as high as the reaction centre proteins of photosystem II and the Cyt f. These results provide that during senescence, proteins of thylakoid membranes degrade in a specific temporal sequence and thereby affect the temporal photochemical functions in Cucumis sativus cotyledons.

Senescence induced structural reorganization of thylakoid membranes in Cucumis sativus cotyledons; LHC II involvement in reorganization of thylakoid membranes

We report the formation and appearance of loosely stacked extended grana like structures along with plastoglobuli in the chloroplasts isolated from 27-day old senescing cucumber cotyledons. The origin and the nature of these extended grana structures have not been elucidated earlier. We isolated Photosystem I complexes from 6-day-old control and 27-day-old senescing cotyledons. The chlorophyll a/b ratio of the isolated Photosystem I complex obtained from 6-day cotyledons was 5-5.5 as against a ratio of 2.9 was found in Photosystem I complexes obtained from 27-day-old senescing cotyledons. We also found that the presence of LHC II in the Photosystem I complexes isolated from 27-day cotyledonary chloroplasts. The presence of LHC II in Photosystem I complexes in senescing and not in control samples, clearly suggest the detachment and diffusion of LHC II complexes from stacked grana region to Photosystem I enriched stroma lamellar region thereby, forming loose disorganized extended grana structures seen in the transmission electron microscope. Furthermore, we show that under in vitro condition the senescing cotyledon chloroplasts exhibited lower extent of light induced phosphorylation of LHC II than the control samples suggesting a possible irreversible phosphorylation and diffusion of LHC II in vivo during the progress of senescence in Cucumis cotyledons. From these findings, we suggest that the senescence induced phosphorylation of LHC II and its migration towards Photosystem I may be a programmed one some how causing the destruction of the thylakoid membrane. The released membrane components may be stored in the plastoglobuli prior to their mobilization to the younger plant parts.

Seroprevalence of HIV, HBV, and syphilis and associated risk behaviours in male transvestites (Hijras) in Karachi, Pakistan

In Pakistan, male sex workers are predominantly transvestites and transsexuals known as Hijras. In 1998 in Karachi, Pakistan, we studied the seroprevalence of HIV, HBsAg and syphilis and associated risk factors in Hijras. Study subjects were verbally administered a structured questionnaire that determined risk behaviours for sexually transmitted and blood-borne diseases and knowledge of AIDS/STDs. After pre-test counselling, verbal consent was taken for serological testing. The results were provided on a one-on-one post-test counselling session. Three hundred male transvestites were approached; all agreed to answer the questionnaire, 208 consented to blood testing. Of 300, 81% acknowledged commercial sex with men. Of 208, prevalence of syphilis was 37%; HBsAg 3.4%; HIV 0%. The prevalence of HIV and hepatitis B virus (HBV) is low in transvestite sex workers but that of syphilis is high. Intervention programmes implemented at this stage can have an impact on HIV and STD prevention.

Age dependent alterations in photosystem II acceptor side in Cucumis sativus cotyledonary leaf thylakoids: analysis of binding characteristics of herbicide [14C]-atrazine

Senescence induced temporal changes in photosystems can be conveniently studied in cotyledonary leaves. We monitored the protein, chlorophyll and electron transport activities in Cucumis sativus cv Poinsette cotyledonary leaves and observed that by 20th day, there was a 50%, 41% and 30-33% decline in the chlorophyll, protein and photosystem II activity respectively when compared to 6th day cotyledonary leaves taken as control. We investigated the changes in photosystem II activity (O2 evolution) as a function of light intensity. The photosystem II functional antenna decreased by 27% and the functional photosystem II units decreased by 30% in 20-day old cotyledonary leaf thylakoids. The herbicide [14C]-atrazine binding assay to monitor specific binding of the herbicide to the acceptor side of photosystem II reaction centre protein, D1, showed an increase in the affinity for atrazine towards D1 protein and decrease in the QB binding sites in 20th day leaf thylakoids when compared to 6th day leaf thylakoids. The western blot analysis also suggested a decrease in steady state levels of D1 protein in 20th day cotyledonary leaf thylakoids as compared to 6th day sample which is in agreement with [14C]-atrazine binding assay and light saturation kinetics.

The induction of neurotrophin and TRK receptor mRNA expression during early avian embryogenesis

Nerve growth factor, brain-derived neurotrophic factor and neurotrophin-3, designated neurotrophins, are a family of neurotrophic factors, having important functions in the survival of embryonic and adult neuronal subpopulations. Through the trk family of receptors, these neurotrophins utilize phosphotyrosine-mediated signal transduction. We have used RT-PCR to detect the expression of mRNA for the above neurotrophins and their respective receptors, namely trkA, trkB and trkC in embryonic stages 1-8 of chicken development. While trkA and trkC mRNAs were expressed from stage 1 onwards, NGF and NT-3 mRNAs were expressed only at stages 3 and 5, respectively. In contrast, BDNF mRNA was expressed at stage 1, being the only neurotrophin expressed prior to expression of its respective receptor trkB. However, the latter was not expressed until stage 8. These results indicate an earlier expression of some but not all trk proto-oncogenes, suggesting that the two different receptor mRNAs expressed i.e. trkA and trkC in conjunction with BDNF, at stage 1, may act in aspects of very early embryonic development, such as gastrulation. Thereafter, mRNAs for trkB, NGF and NT-3 are expressed reflecting their later action in early embryonic development.

Antigen dependent adjuvant activity of a polydispersed beta-(1,4)-linked acetylated mannan (acemannan)

The adjuvant properties of a polydispersed beta-(1,4)-linked acetylated mannan, acemannan (ACE-M), were evaluated. Day-old broiler chicks were randomly selected and allocated to four flocks (Vac 1-4). The Vac 1 flock was sham vaccinated with saline. The Vac 2 flock was vaccinated with an oil-based vaccine (Breedervac III; Newcastle disease virus (NDV), infectious bursal disease virus (IBDV) and infectious bronchitis virus). The Vac 3 flock was vaccinated with a vaccine-ACE-M mixture, and the Vac 4 flock was vaccinated with vaccine and ACE-M at separate anatomical sites. ELISA titres to NDV and IBDV were determined. The immune response to NDV at 21 days postvaccination (PV) was significantly enhanced (P less than or equal to 0.05) by the addition of ACE-M to the vaccine, compared with vaccination without ACE-M. Subsequently, the vaccine-ACE-M mixture appeared to suppress the immune response to NDV. However, at day 35 PV, 95% of the Vac 3 chicks compared with 90% of the Vac 2 and 89% of the Vac 4 chicks exhibited protective titres. The response to IBDV differed from that to NDV. At day 21 PV the immune response to IBDV was essentially the same for all flocks that received vaccine, i.e. addition of ACE-M to the vaccine did not significantly enhance the immune response; however, it did significantly (P less than or equal to 0.05) sustain the immune response at days 28 and 35. In addition to the observed effect on titres to NDV and IBDV, ACE-M also had an effect on flock immunity.(ABSTRACT TRUNCATED AT 250 WORDS)