Bluetongue virus seropositivity in sheep flocks in North West Frontier Province, Pakistan

The objectives of this study were to describe the prevalence and distribution of serum antibodies to Bluetongue virus (BTV) in a sample of 38 sheep flocks in northern areas of the North West Frontier Province of Pakistan and to identify demographic and productivity variables that are associated with BTV seropositivity. Blood samples were taken from a random sample of ewes in each flock in April 1995. The owners of the flocks were interviewed regarding some demographic, husbandry and productivity variables of the flocks on the day of blood sampling. A competitive enzyme-linked immunosorbent assay was conducted to test the serum samples for BTV group-specific antibodies. BTV seropositive reactions were obtained in 184 (48.4%) out of 380 tested sera, and in 89.5% (34/38) of the flocks. In the 34 seropositive flocks, the prevalences ranged from 12.5 to 100% (median = 47). A multivariable logistic analysis was carried out to study the influence of demographic and productivity variables on the BTV serological status of the sheep flocks. Abortion risk in the previous lambing season was mildly associated with the serological status of the flock (adjusted odds ratio = 1.16, P = 0.07). For the seropositive flocks, a linear multiple regression showed that distance travelled by the flock during transhumant movement was significantly associated with percent seropositivity (partial regression coefficient (± SE) = − 0.091 ± 0.045).     

2种昆虫病原真菌对草地贪夜蛾体表侵染模式的扫描电镜观察

【目的】在前期筛选获得对草地贪夜蛾高效致病真菌球孢白僵菌（Beauveria bassiana）菌株GZSL-1和玫烟色虫草（Cordyceps fumosorosea）菌株IFCF01的基础上,进一步明确2株菌株在草地贪夜蛾体表的侵染模式,为阐明菌株致病机理,提高昆虫病原真菌对草地贪夜蛾的防效提供理论依据。【方法】利用扫描电镜观察草地贪夜蛾2龄幼虫分别接种菌株GZSL-1和IFCF01（孢子悬浮液浓度为1.0×107孢子/mL）后分生孢子在幼虫体表附着、萌发、穿透和增殖的过程。【结果】菌株GZSL-1和IFCF01萌发后均可形成附着胞,草地贪夜蛾幼虫体表结构对2株菌株分生孢子萌发、附着和穿透芽管长度有不同程度的影响。2株菌株在各结构区均有较高的萌发率（> 90.00%）和附着胞率（> 80.00%）,在平缓结构区比瘤状突起结构区观察到更短的穿透芽管。在各结构区,菌株GZSL-1形成的穿透芽管长度均短于菌株IF-CF01相应的芽管长度,在平缓结构区,菌株GZSL-1的穿透芽管长度显著短于菌株IFCF01（P<0.05）。菌株GZSL-1和IFCF01分生孢子接种后分别在16和8 h内萌发,在24和32 h内普遍出现穿透结构穿透草地贪夜蛾幼虫体壁。2株菌株的初级和次级分生孢子分别在接种后72和96 h内出现。【结论】扫描电镜观察证实球孢白僵菌菌株GZSL-1和玫烟色虫草菌株IFCF01对草地贪夜蛾具有高致病性,揭示了病原真菌分生孢子在草地贪夜蛾虫体上的侵染过程,结果为后续2株菌株的改良及田间应用打下理论基础。     

Phosphorus Stress-Induced Differential Growth,and Phosphorus Acquisition and Use Efficiency by Spring Wheat Cultivars

ABSTRACT

Phosphorus (P) is a finite, non-renewable, and natural resource and a vital major nutrient for plant metabolic and developmental processes. However, adverse soil biogeochemical characteristics of alkaline-calcareous soils (especially Aridisols) and highly weathered acid soils (i.e., Ultisols and Oxisols) render orthophosphate (Pi) as the least available major nutrient due to P complexation, sorption, and/or fixation. In such soil environments, plant bioavailable P is only a small fraction of total soil P, seriously limiting crop growth and production. Different plant species, and even cultivars of the same species, may display a suite of growth responses that enable them to solubilize and scavenge soil P either by enhancing external Pi acquisition or reprioritizing internal Pi use under P-stress soil environments. This paper reports relative growth responses, P acquisition and P-use efficiency characteristics by 14 cultivars of spring wheat (Triticum aestivum L.) grown in solution culture with high/low P supply induced by applying soluble NH₄H₂PO₄, sparingly soluble rock phosphate, and Ca₃(PO₄)₂. The wheat cultivars exhibited considerable genetic diversity in biomass accumulation, P concentrations, P contents, factor (PSF) and P efficiency characteristics [i.e., P utilization efficiency (PUE), P efficiency (PE), and PE ratio (PER)]. Plant growth and PE parameters were significantly correlated, while P uptake was linearly related with biomass increase and solution pH decrease. The wheat cultivars with high PUE, PER and P uptake, and low PSF, and plant P concentration were more efficient in utilizing P and, hence, more tolerant under P-stress environment. Biomass and P contents of “P efficient/low-P tolerant” wheat cultivars were superior to “P inefficient/low-P sensitive” cultivars at all P-stress levels. Hence, “P efficient/low-P tolerant” cultivars are the most desirable wheat genotypes for P-stress environments because they are able to scavenge more P from sparingly soluble P sources or soil-bound P forms.     

Selenium supplementation reduced oxidative stress in diethylnitrosamine-induced hepatocellular carcinoma in rats

Selenium in the form of sodium selenite (SSE) is an essential micronutrient which known to possess antioxidant and anticancer properties. This study emphasizes the role of selenium on oxidative stress in experimental rats with N-diethylnitrosamine (DEN) initiated and 2-acetylaminofluorene (2-AAF) promoted multistage hepatocellular carcinogenesis (HCC). Rats were divided randomly into six groups: negative control, positive control (DEN+2-AAF), preventive group (pre-SEE 4 weeks+DEN), preventive control (respective control for preventive group), therapeutic group (DEN+post-SSE 12 weeks) and therapeutic control (respective control for therapeutic group). SSE (4 mg L(-1)) was given to animals before initiation and during promotion phase of HCC. The levels of total protein (TP), conjugated diens (CD), malondialdehyde (MDA), fluorescent pigment (FP), antioxidant activity (AOA) and DNA damage were measured. Supplementation of SSE before the initiation phase of carcinogenicity significantly increased TP and AOA level (p < 0.05) while it decreased the levels of CD, MDA, DNA damage and FP (p < 0.05). Supplementation of SSE during the promotion phase of carcinogenicity significantly decreased the DNA damage and FP level (p < 0.05) and there were negative correlation between the level of AOA and with the level of FP and CD. Thus, supplementation of SSE reduced the adverse changes which occur in liver cancer. However, the chemoprevention effect of SSE was more pronounced when it was supplemented before initiation phase of cancer when compared to promotion phase.     

Different Eucalyptus Species Show Different Mechanisms of Tolerance to Salinity and Salinity × Hypoxia

ABSTRACT

We studied the effect of sodium chloride (NaCl) salinity and oxygen deficiency stress on growth and leaf ionic composition of three Eucalyptus species [E. tereticornis, E. camaldulensis (Silverton), and E. camaldulensis (Local)]. Species were grown with control (no NaCl) and salinity (150 mol m^?3 NaCl) under hypoxic and non-hypoxic conditions in nutrient solution with five replications following CRD. Species differed significantly in their response to salinity and hypoxia. Absolute shoot dry matter was significantly better in E. camaldulensis (Silverton) in salinity and in E. camaldulensis (Local) in saline hypoxic treatment. E. tereticornis was the most sensitive species to salinity and salinity × hypoxia in the root environment. Sodium (Na⁺) and chloride (Cl^?) concentrations were significantly lower in E. camaldulensis (Local) in non-hypoxic saline treatment compared to the other two species. E. camaldulensis (Silverton) seems to have better tissue compartmentalization, whereas E. camaldulensis (local) seems to have better exclusion of Na⁺ at the root level.     

Asociacion Latinoamericana de Especialistas en Las Ciencias Aplicadas a Las Malezas (ALAM)

Abstract

ENTOMOGENOUS NEMATODES, A MANUAL AND HOST LIST OF INSECT-NEMATODE ASSOCIATIONS. G. O. Poinar, Jr. E. J. Brill, Leiden, 175. ISBN 90 04 04240 7. Pp. 317. Price Dutch Guilders 96.

PESTICIDE INDEX. Fifth edition. Edited by W. J. Wiswesser. Entomological Society of America, 1976. Pp. 328. Price US $12.00.

ENVIRONMENTAL DYNAMICS OF PESTICIDES. Edited by Rizwanul Haque and V. H. Freed. Plenum Press, New York and London, 1975. ISBN 0 306 36306 2. Pp. viii + 387. Price £15.65.

TOXICOLOGY OF INSECTICIDES. Fumio Matsumura. Plenum Press, New York and London, 1975. ISBN 0 306 30787 1. Pp. xvii + 503. Price £14.60.

CROP PRODUCTION PRINCIPLES AND PRACTICES. S. R. Chapman and L. P. Carter. W. H. Freeman &; Co., San Francisco, USA and Reading, England, 1976. ISBN 0–7167–0581–8. Pp. 566. Price £9.50.

DISEASES OF TROPICAL AND SUBTROPICAL FRUITS AND NUTS. A. A. Cook. Hafner Press, New York, 1975. Pp. 317. Price US $20.00.

MORE DEMATIACEOUS HYPHOMYCETES. M. B. Ellis. Commonwealth Mycological Institute, Kew, Surrey, 1976. ISBN 0 85 198 365 0. Pp. 507. Price £15.00 in UK, £18.00 overseas.

AN ANNOTATED BIBLIOGRAPHY OF COLOUR ILLUSTRATED MINERAL DEFICIENCY SYMPTOMS IN TROPICAL CROPS. Technical Communication No. 34 of the Commonwealth Bureau of Horticulture and Plantation Crops. J. B. D. Robinson. Commonwealth Agricultural Bureaux, Farnham Royal, UK, 1974. ISBN 0 85198 304 9. Pp. 84. Price £5.00 UK, £6.00 overseas. First Supplement, 1976. Price £1.50 UK, £1.80 overseas.

NUTRITION IN PREVENTIVE MEDICINE. WHO Monograph Series, No. 62. G. H. Beaton and J. M. Bengoa. WHO, Geneva, 1976. ISBN 92 4 140062 5. Pp. 590. Price Sw. fr. 83.

ECONOMICALLY APPROPRIATE TECHNOLOGIES FOR DEVELOPING COUNTRIES: AN ANNOTATED BIBLIOGRAPHY. M. Carr. Intermediate Technology Publications Ltd., London, 1976. ISBN 0 903031 19 1. Pp. 101. Price: £2.00 net; £2.25 UK post paid; £3.15 airmail; £2.30 surface mail.

CHINESE CHAIN AND WASHER PUMPS. S. Watt. Intermediate Technology Publications Ltd., London, 1976. ISBN 0 90301 26 4. Pp. 49. Price: £0.95 net; £1.15 UK post paid; £1.65 airmail; £1.25 surface mail.

A MANUAL ON BUILDING MAINTENANCE – Volume 1: Management and Volume 2: Methods. D. Miles. Intermediate Technology Publications Ltd., London, 1976. ISBN 0 903031 28 0. Vol. 1 pp. 78, Vol. 2. pp. 64. Price for each volume: £1.25 net; £1.50 UK post paid; £2.20 airmail; £1.55 surface mail.

AGRICULTURAL RESEARCH FOR DEVELOPMENT. THE NAMULONGE CONTRIBUTION. Edited by M. H. Arnold. Cambridge University Press, 1976. Pp. xi + 353. ISBN 0 521 21051 8. Price £13.00.

SURVEY OF THE WORLD'S APHIDS. V. F. Eastop and D. Hille Ris Lambers. Dr W. Junk B.V., The Hague, 1976. ISBN 90 6193 561 X. Pp. 573. Price Dutch Guilders 160.

CONTROLLED-DROPLET APPLICATION AND U.L.V. SPRAYING. Anon. BP Ltd., London, 1976. Pp. 28. Price: free. Available from: Agricultural Branch, International Marketing Department, BP Trading Ltd, Britannic House, Moor Lane, London EC2Y 9BU, UK.

ANNUAL REVIEW OF PHYTOPATHOLOGY, Volume 14, 1976. Edited by K. F. Baker, G. A. Zentmyer and E. B. Cowling. Annual Reviews Inc., Palo Alto, California, USA. ISBN 0 8243 1314 3. Pp. 511. Price US $17.00 (USA), US £17.50 (elsewhere).

INTEGRATED PEST MANAGEMENT. Edited by J. Lawrence Apple and Ray F. Smith. Plenum Press, New York. 1976. ISBN 0 306 30929 7. Pp. 200. Price US $48.50.

INSECTICIDE BIOCHEMISTRY AND PHYSIOLOGY. Edited by C. F. Wilkinson. Plenum Press, New York and London, 1976. ISBN 0 306 30872 X. Pp. 768. US $59.40 (UK £31.19).