Genotypic, phenotypic, biochemical, physiological and pathogenicity-based categorisation of Acanthamoeba strains

The genus Acanthamoeba includes more than 20 morphological species, but classification is problematical. Recently, the discovery of substantial interstrain differences in ribosomal DNA (rDNA) sequences has prompted questions about the relatedness of strains of the same species. In this study, therefore, we have investigated relationships between two isolates of A. polyphaga, CCAP 1501/3c and ATCC 30871, using morphological, biochemical, physiological, molecular and cytotoxicity assays. We observed that A. polyphaga ATCC 30871 exhibited up to six arms in endocyst while A. polyphaga CCAP 1501/3c exhibited a maximum of 5 arms thus indicating their position in group 2 and 3, respectively. Acanthamoeba polyphaga ATCC 30871 exhibited growth at 37 degrees C and growth on 1M mannitol plates while A. polyphaga CCAP 1501/3c did not. In addition, both isolates exhibited differences in isoenzyme banding patterns and rDNA restriction fragment polymorphisms. More importantly, A. polyphaga ATCC 30871 produced cytotoxicity on corneal epithelial cells while A. polyphaga CCAP 1501/3c had no effects, suggesting differences in pathogenicity. Thus, all the results provide evidence for significant differences between the strains and further provided the basis for reclassification of the isolates. Implications of these results in the clinical diagnosis of pathogenic Acanthamoeba are discussed.     

Improved fruit retention,yield and fruit quality in mango with exogenous application of polyamines

Aqueous solutions (0, 0.01, 0.1, 1 mM) of PAs (putrescine, spermine, spermidine) containing a surfactant ‘Tween 20’ were sprayed onto panicles of mango (Mangifera indica L. cv. Kensington Pride) at final fruit set (FFS) stage (when all flowers abscised but remain attached to the panicle) during 1999–2001 to investigate their effects on fruit retention, yield, size, and fruit quality. The optimum time of PA application for improving final fruit retention and fruit yield was determined by spraying different concentrations (0, 0.01, 0.1, 1 mM) of spermine (SPM) containing a surfactant ‘Tween 20’ at four phenological stages including flower bud differentiation (FBD), 5–8 cm long grown panicles (GP), full bloom (FB) and at initial fruit set (IFS) stage (when 2/3rd of the flowers were abscised but attached to the panicle) during 2000. Exogenous application of PAs at FFS stage did not significantly increase fruit retention. However, compared to control (0.79 and 2.3% fruit retention), PAs treatments resulted in comparatively higher mean fruit retention (1.53 and 2.92%) during 1999–2000 and 2000–2001, respectively. Among three PAs tested, SPM was more effective in increasing mean final fruit retention. Fruit size was not significantly affected by any PA treatment. Among the four application times, SPM (0.01 mM) spray at FB stage resulted in significantly (P ≤ 0.05) greater fruit retention (4.99%) compared with control (2.1%). However, fruit yield was comparatively higher with SPM (0.01 mM) application at IFS stage or 5–8 cm GP stage compared to the control. Overall FB application was found as the optimum time of application. Application of PAs at FFS stage retarded fruit skin colour development compared to the control. Sugars and total soluble solids (TSS) were generally reduced in PA-treated fruit. Fruit acidity was increased (16.7%) with SPM, whereas it was 11% with PUT treatment as compared to the control. Total carotenoids in pulp were generally improved (49%) with PA treatments, compared to the control. Ascorbic acid concentrations were significantly reduced with spermidine (SPD) (24%) and PUT (20%) treatments, whereas higher concentrations of SPM (1 mM) tended to increase it (12.7%) compared to the control. In conclusion, application of SPM (0.01 mM) at FB stage resulted in the highest fruit retention, whereas SPM (0.01) spray at GP or IFS stage resulted in higher fruit yield. PUT application at FFS stage significantly improved fruit quality by increasing total carotenoid, while reducing acid content of ripe fruit.     

First record of Oomyzus scaposus (Hymenoptera: Eulophidae), as a parasitoid of Coccinella septempunctata (Coleoptera: Coccinellidae) in Pakistan

Coccinella septempunctata L. (Coleoptera: Coccinellidae) is a natural enemy of several important pests. This biocontrol agent is also a host for different parasitoids. Little is known about the parasitoid complex of C. septempunctata in Pakistan. The authors identified Oomyzus scaposus (Thomson, 1878) (Hymenoptera: Eulophidae) as a larval-pupal parasitoid of C. septempunctata in the district of Sargodha, Punjab, Pakistan. Out of 36 C. septempunctata pupae collected, 58.3% were parasitized by O. scaposus. This study documents the first record of O. scaposus parasitizing C. septempunctata in Pakistan.     

Response of juvenile pacu (Piaractus mesopotamicus Holmberg, 1887) to balanced digestible protein

This 45‐day work aimed to determine the response of juvenile pacu (Piaractus mesopotamicus) to balanced digestible protein (BDP) and to use these responses to determine whether the optimum economic levels of BDP would differ depending on the form in which the fish is sold. Six isoenergetic diets containing 163, 201, 238, 272, 315 and 348 g/kg BDP (dry‐matter basis) were prepared through the serial dilutions of a high‐protein diet with the low‐protein diet. Fish (initial average body weight, 10.82 ± 0.14 g) were fed with respective experimental diets three times a day until apparent satiation. The optimum biological level of BDP was calculated as 326 g/kg (dry‐matter basis) by the quadratic regression model for maximum body weight gain of juvenile pacu. To maximize economic returns (US$/kg) for different end products, the optimum economic levels of BDP were calculated as 311, 317 and 319 g/kg (dry‐matter basis) by an economic model for whole‐body, eviscerated and sliced juvenile pacu respectively. This finding revealed that obtaining maximum biological performance of fish in the case of high feed costs or low prices of the end product in consumer market would substantially reduce the economic returns.     

Biological effects of indigenous medicinal plants Curcuma longa and Alpinia galanga

The ethanolic extracts of Curcuma longa and Alpinia galanga exhibited excellent (100%) phytotoxic activity against Lemma minor. These extracts were also found to possess good antifungal activities against Trichophyton longifusus (65% and 60%, respectively), while in the brine shrimp lethality bioassay were found to be toxic with LD50 of 33 and 109 mincrog/ml, respectively. These extracts were found quite inert in antibacterial bioassay, while the extract from C. longa, tested for insecticidal activity, was also found to be devoid of any activity.     

Influence of Zn nutrition on the productivity,grain quality and grain biofortification of wheat under conventional and conservation rice–wheat cropping systems

ABSTRACT

This study was conducted to evaluate influence of zinc (Zn) application on productivity, grain biofortification and grain quality of wheat planted under plough tillage (PT) and zero tillage (ZT) systems. Zn was delivered as soil application (10 kg ha^?1), foliage spray (0.025 M) and seed priming (0.5 M) in wheat planted under PT and ZT systems. ZT had higher total soil porosity, total soil organic matter, soil organic carbon and soil microbial biomass carbon than PT. Zn application, by either method, improved grain yield, grain Zn and grain quality in both tillage systems. The grain Zn concentration was 72% and 59% higher with soil-applied Zn in ZT wheat during 2016–2017 and 2017–2018, respectively, compared with no Zn. However, Zn seed priming was the most effective in improving wheat grain yield in both tillage systems. Foliage and Zn soil application were better in improving the indices of Zn use efficiency of Zn. In conclusion, Zn seed priming was the most effective method in improving the wheat grain yield, whereas soil Zn application in ZT and foliar applications in PT were the most effective for grain Zn biofortification. However, Zn soil application was the most cost-effective method of Zn application.     

Assessing the fate of recombinant plant DNA in rabbit’s tissues fed genetically modified cotton

Various feeding studies have been conducted with the different species of animals to evaluate the possible transfer of transgenic DNA (tDNA) from genetically modified (GM) feed into the animal tissues. However, the conclusions drawn from most of such studies are sometimes controversial. Thus, in the present study, an attempt has been made to evaluate the fate of tDNA in rabbits raised on GM cotton-based diet through PCR analysis of the DNA extracted specifically from blood, liver, kidney, heart and intestine (jejunum). A total of 48 rabbits were fed a mixed diet consisting variable proportions of transgenic cottonseeds meal (i.e. 0% w/w, 20% w/w, 30% w/w and 40% w/w) for 180 days. The presence of transgenic DNA fragments (Cry1Ac, Cry2A and CP4 EPSPS) or plant endogenous gene (Sad1) was traced in those specific tissues and organs. The presence of β-actin (ACTB) was also monitored as an internal control. Neither the transgenic fragments (459 bp of Cry1Ac gene, 167 bp of Cry2A gene and111 bp of CP4 EPSPS gene) nor cotton endogenous reference gene (155 bp of Sad1) could be detected in any of the DNA samples extracted from the rabbit's tissues in both control and transgenic groups. However, 155 bp fragment of the rabbit's reference gene (ACTB) was recovered in all the DNA samples extracted from rabbit tissues. The results obtained from this study revealed that both plant endogenous and transgenic DNA fragments have same fate in rabbit's tissues and were efficiently degraded in the gastrointestinal tract (GIT).     

Influence of multi-enzyme preparation supplemented with sodium butyrate on growth performance blood profiles and economic benefit of growing rabbits

The present study was carried out to explore the impacts of dietary supplementation of enzyme mixture with sodium butyrate on the growth performance, carcass traits, blood profile and economic benefit in two breeds of weanling rabbits adapted to survive in Egypt (New Zealand White and Rex). One-hundred and twenty weaned male rabbits (New Zealand White and Rex) of 6 weeks of age and 770.5 ± 20 g body weight were allotted randomly into four groups in a factorial arrangement. The obtained results indicated that there were non-significant differences in all growth performance traits, blood profile and economic parameters due to the breed effect. However, there were significant differences in most of carcass traits due to the breed effect except total giblets and New Zealand White breed showed the highest value of these parameters including dressing % (p < .01), forequarter and loin % (p < .001) and hindquarter % (p < .003) compared with Rex breed counterparts. The effect of the treatment and its interaction with the breed significantly (p < .05) improved body weight gain, feed consumption and carcass traits (percentage of dressing, forequarter, hind quarter and lion). However, final body weight and feed conversion ratio were not significantly influenced. Supplementing a diet with treatment significantly decreased blood triglycerides, cholesterol and the ratio between albumin and globulin (A/G ratio), while increased blood total protein and globulin. Although higher feed cost and total costs in treated groups than control ones in each breed, they showed higher total return and net return. Rex non-treated rabbit breed showed the lowest profitability measures compared with other groups. In conclusion, dietary supplementation of multi-enzyme with sodium butyrate is highly recommended in growing rabbits due to their beneficial effects on the growth performance and profitability.     

Genetic identity of the Bemisia tabaci species complex and association with high cotton leaf curl disease (CLCuD) incidence in Pakistan

BACKGROUND: The cotton whitefly, Bemisia tabaci (Gennadius), is a cryptic species complex, and members of the complex have become serious pests in Pakistan because of their feeding and their ability to transmit cotton leaf curl virus (CLCuV). Here, an analysis was made of the identity of B. tabaci collected from cotton and a range of non‐cotton hosts in the cotton‐growing zones in Punjab and Sindh, the main cotton‐producing provinces of Pakistan, using a portion of the mitochondrial cytochrome oxidase 1 gene. The geographic distribution of the different members of the complex was then compared with the incidence of CLCuD. RESULTS: Using the Dinsdale nomenclature, the results revealed three putative species, Asia 1, Asia II 1 and Middle East‐Asia Minor 1. Asia II 1 (also referred to in the literature as biotypes K, P, PCG‐1, PK1, SY and ZHJ2) was only recorded from Punjab cotton plants, whereas Asia 1 (also referred to in the literature as biotypes H, M, NA and PCG‐2) was found in both Sindh and Punjab. Middle East‐Asia Minor 1 (commonly known as biotype B and B2) was found only in Sindh. Moreover, Asia II 1 was associated with high incidences of CLCuD, whereas regions where Middle East‐Asia Minor 1 was present had a lower incidence. Phylogenetic analysis showed that the Middle East‐Asia Minor 1 population in Sindh formed a distinct genetic subgroup within the putative species, suggesting that the Sindh province of Pakistan may form part of its home range. So far, no individuals from the putative species Mediterranean (commonly known as biotypes Q, J and L) have been found in Pakistan. CONCLUSIONS: The capacity to manage pests and disease effectively relies on knowledge of the identity of the agents causing the damage. In the case of CLCuD in Pakistan, this knowledge has been obscured to some extent because of the inconsistent approach to identifying and distinguishing the different B. tabaci associated with CLCuD. The situation has now been clarified, and a strong association between disease incidence and vector identity and abundance has been shown. Given this advance, future research can now focus on factors that influence the capacity of different vector species to transmit the viruses that cause CLCuD, the reason for differences in vector abundance and the lack of geographic overlap between the cryptic vector species. This knowledge will contribute to the development of improved methods with which to manage the disease in Pakistan. Copyright © 2010 Society of Chemical Industry     

Comparative effectiveness of Pseudomonas and Serratia sp. containing ACC-deaminase for coinoculation with Rhizobium leguminosarum to improve growth, nodulation, and yield of lentil

Three plant growth-promoting rhizobacteria strains containing ACC-deaminase (Pseudomonas jessenii, Pseudomonas fragi, and Serratia fonticola) and Rhizobium leguminosarum were selected and characterized by conducting some experiments under axenic condition. The selected isolates had the potential to improve the growth of lentil seedlings under axenic conditions. Pot and field experiments were conducted to evaluate the potential of these selected strains for improving growth and yield of lentil under natural conditions. A classical triple response (reduction of stem elongation, swelling of hypocotyle, and change in the direction of growth) bioassay was also conducted to evaluate the effect of high ethylene concentration on the growth of etiolated lentil seedlings, and the performance of coinoculation was evaluated to reduce the classical triple response in comparison with cobalt (Co²⁺), a chemical inhibitor of ethylene. Results showed that coinoculation of Pseudomonas and Serratia sp. with R. leguminosarum significantly increased the growth and yield of lentil. However, synergistic/coinoculation effect of P. jessenii with R. leguminosarum was more pronounced compared to that with P. fragi and S. fonticola. It increased the number of pods per plant, number of nodules per plant, dry nodule weight, grain yield, and straw yield up to 76%, 196%, 109%, 150%, and 164% under pot and up to 98%, 98%, 100%, 82%, and 78%, respectively, under field conditions as compared to uninoculated control. Similarly, combined inoculation significantly increased N concentration of grains under both pot and field conditions. The results from classical triple response assay showed that the effects of classical triple response decreased due to coinoculation in etiolated lentil seedlings and due to a decrease in the ethylene concentration. It is suggested that the strategy adopted by Pseudomonas sp. containing ACC-deaminase with Rhizobium to promote nodulation and yield by adjusting ethylene levels could be exploited as an effective tool for improving growth, nodulation, and yield of lentil.