Determinants influencing prevalence of louse infestations on layers of district Faisalabad (Pakistan)

1. This paper describes the influence of some epidemiological determinants on the prevalence of louse infestation on layers in Faisalabad (Pakistan). 2. Seventy layer farms were screened to determine the prevalence of louse infestation and its determinants including age of the bird, availability of space per bird and frequency of litter change. Prevalence of Lipeurus caponis was highest (53.2%), followed by Menacanthus stramineus (22.16%), Goniodes dissimilis (12.37%) and Goniodes gallinae (12.37%). 3. Older birds (36 to 74 weeks of age) were found with a significantly higher prevalence of louse infestation than younger birds. 4. Month-wise prevalence of louse infestation was higher during the summer months (from April to August) and at older age. 5. Birds kept at floor area allowances ranging from 0.43 to 0.55 m(2) were highly infested with lice as compared to those provided with a space of 0.61 m(2) or higher per bird. 6. Litter change frequency after every 8 weeks resulted in a reduced chance of louse infestation as compared to less frequent litter changing practice. 7. It was concluded from the study that the louse infestation is a menace for the poultry production industry in Pakistan and age, space per bird and litter change frequency are the influencing determinants. 8. Further research on the chemotherapeutic trials and resistance in poultry should be continued for an effective lice control program.     

Incidence of human malaria infection in northern hilly region of Balochistan, adjoining with NWFP, Pakistan: district Zhob

This study was conducted to investigate the incidence of malarial infections in human population in 37 localities of district Zhob, Balochistan, Pakistan. Malarial parasites were identified in the blood slides of suspected patients of the disease from July, 2004 to June, 2006 and encompassed 7748 subjects. Out of 7748 suspected cases of malaria, 3240 (41.8%) were found to be positive for malarial parasite in blood smear slides. Out of positive cases, 1681 (51.8%) were identified as Plasmodium vivax infection and 1559 (48.1%) cases with P. falciparum. However, seasonal variation was also noted with the highest (85.4%: 141/165) infection of P. vivax in March and lowest (18.6%: 59/316) in October while infection of P. falciparum was highest (81.3%: 257/316) in October and lowest (14.5%: 24/165) in March. Infection with P. vivax in male was 75.7% (125/165) in March and in female 26.3% (58/220) in May whereas infection of P. falciparum in male was 61.5% (245/398) in July and in female was 20.5% (65/316) in October. These results are compared with those of other studies done in Pakistan. Cases of P. malariae and P. ovale were not found in the present study. In conclusion it can be pointed out that the high incidence rate of P. vivax (51.8%:1681/3240) in Zhob district poses a significant health hazard because it may also lead to cerebral malaria as it was suggested by previous workers.     

Callus induction and in vitro plant regeneration of rice (Oryza sativa L.) under various conditions

The objective of the present study was to develop an effective protocol for optimum callus induction and complete plant regeneration for four varieties of rice (Oryza sativa L.) i.e., Super Basmati, Basmati-370, Basmati-371 and Fakhre Malakand. Calli were induced from mature seed scutelum. The Murashige and Skoog (MS) and Chu's N6 media containing hormone 2, 4-D (2, 4-Dichlorophenoxy acetic acid) in different concentrations were used for callus induction. Fakhre Malakand produced maximum calli on N6 media containing 3 mg L(-1) 2,4-D. while other three varieties showed maximum callus induction on N6 media containing 2.5 mg L(-1) 2,4-D. N6 media was found better than MS media for callus induction. For complete plant regeneration the calli of two varieties i.e., Basmati-370 and Basmati-371 were plated on N6 media containing different concentrations of NAA (1-Naphthalene acetic acid) and BAP (6-benzyl aminopurine). The maximum regeneration frequency (%) was observed on N6 media containing NAA 1 mg L(-1) and BAP 2.5 mg L(-1). It took 27-30 days for the callus to regenerate into a complete plant. Basmati-370 produced 4-7 plantlets per callus whereas Basmati-371 produced 4-8 plantlets per callus with regeneration frequencies of 61 and 69%, respectively.     

Callogenic studies of Achyranthes aspera leaf explant at different hormonal combinations

With the objective to promote in vitro callus induction, leaf segments of Achyranthes aspera were inoculated on basal MS medium supplemented with 3.0% sucrose and 0.8% agar with different concentrations of 2,4-D alone and in combination with NAA, BAP, IAA, IBA and Zeatin. The explants were maintained in growth room at 25 +/- 1 degrees C and 16 h light cycle. The best callus induction was obtained with 2,4-D (1.0 and 2.0 mg L(-l)) in combination with NAA (0.5 mg L(-1)). Callus induction and good texture from leaf explant was also observed at 2,4-D with BAP. On these combinations morphologically, light green, soft, compact and non-embryogenic callus (Type III callus) was observed. While morphology of callus and callogenic response was poor at 2,4-D alone or in combination with other hormones at different concentrations.     

Resistance to foliage feeding aphid in wheat

Experimental trials were conducted at Integrated Pest Management Programme, National Agriculture Research Centre Islamabad, to evaluate the resistance of host plants (cereals) against Rhopalosiphum padi (L.). For evaluation of susceptibility, twenty varieties/-advanced lines of National Uniform Wheat Yield Trails (NUWYT) Normal (N) of year 2004-2005 were used. In seedling bulk tests varieties/advanced lines were grouped into three categories resistant, moderately resistant and susceptible. Data from seedling bulk tests showed that DN-47 and PR 87 lines of wheat were resistant to aphid as compared to the other varieties/-advanced lines. In antixenosis tests varieties/-advanced lines were grouped into three categories, least preferred, moderately preferred, highly preferred. Lines V-01180, DN-47 and PR-84 were least preferred, sixteen varieties/-advanced lines were moderately preferred and only one variety V-9021 was found to be highly preferred.     

A new cytotoxic xanthone from Garcinia rigida

A new xanthone, yahyaxanthone (1), was isolated from Garcinia rigida leaves. Cytotoxicity evaluation showed that 1 was inhibitory to L1210 cell, with an IC50 value 4.08 microg/ml.     

Using synergistic exogenous phytohormones to enhance somatic embryogenesis from leaf explants of a Eucalyptus grandis clone

Somatic embryogenesis (SE) in Eucalyptus spp. has been limited to germinated seeds, flowers, lignotubers or zygotic embryos. The low yield of somatic embryos from leaf explants has hampered progress, even though leaves offer a more viable source of clonal explants from superior selected genotypes. It was hypothesised that SE from leaf explants could be enhanced through pairing of synergistic exogenous plant growth regulators, such as natural auxins with natural cytokinins. Callus and embryo induction using 2,4-dichlorophenoxyacetic acid (2,4-D), α-naphthalene acetic acid (NAA), indole acetic acid (IAA), and indole butyric acid (IBA), each at either 1.0 or 3.0?mg L^?1, indicated that IAA and IBA favoured significantly higher numbers of embryos compared with 2,4-D or NAA. Hence, IAA and IBA were used for subsequent experiments, combining them (at 1.0?mg L^?1) with either the synthetic cytokinin, kinetin, or the natural cytokinin, trans-zeatin, both at 0.1?mg L?1. The combination of trans-zeatin and either IAA or IBA resulted in a significant increase in SE (e.g. 86 ± 17.2% and 23 ± 3.2% for IAA with trans-zeatin and kinetin, respectively), compared with kinetin, or with these auxins alone. Embryo maturation and plantlet regeneration was highest in those calli that were induced with IAA and trans-zeatin, indicating that maturation was dependent on auxin depletion, based on the stability of the analogue used for induction. For the E. grandis clone under study, the use of synergistic plant growth regulators significantly enhanced SE from leaf explants, thus presenting the opportunity to benefit from the advantages that SE offers over conventional organogenesis.     

Glycinebetaine mediates chromium tolerance in mung bean through lowering of Cr uptake and improved antioxidant system

A pot experiment was conducted to evaluate the role of glycinebetaine (GB) in chromium (Cr) tolerance in mung bean (Vigna radiata L.) grown in Cr-stressed soil. Three concentrations of Cr (0, 250 and 500 µM) were tested with three (0, 50 and 100 mM) concentrations of foliar-applied GB. Cr alone led to a significant decrease in plant growth, biomass, and concentrations of chlorophyll a, b and carotenoids. Cr concentration and electrolyte leakage significantly increased in plants with increasing Cr levels in the soil. Lower Cr stress enhanced the activities of superoxide dismutase (SOD), peroxidases (POD) and catalase (CAT), while higher Cr concentrations decreased the activities of these enzymes. Foliar application of GB successfully alleviated toxic effects of Cr on mung bean and increased plant growth, biomass and chlorophyll contents under Cr stress. GB application reduced Cr accumulation and electrolyte leakage in plants and enhanced the activities of antioxidant enzymes in both shoots and roots as compared with Cr treatments alone. These findings suggest that foliar-applied GB alleviated Cr-induced oxidative stress in mung bean by reducing Cr uptake. The protective effect of GB against Cr stress varies with the concentrations of GB and Cr stress applied. Thus, further studies are still needed to specify the concentrations of GB required for detoxification of specific Cr concentrations under various climatic conditions.