A differential series of pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis>) lines delineates fourteen physiological races of <Emphasis Type="Italic">Phytophthora capsici</Emphasis>

The study of the genetics of resistance in pepper to the oomycete pathogen Phytophthora capsici has been complicated due to a lack of use of a common set of pathogen isolates and host genotypes. We have developed a differential series for this system using eleven pepper genotypes and thirty-four isolates of the pathogen from California, New Mexico, North Carolina, and Turkey. Through differential patterns of virulence of the isolates on the hosts, we identified fourteen different physiological races of P. capsici. There appears to be no restriction of races to particular geographical locations. Isolate mating types were also determined, and both mating types were found in one field in California. The significance of the characterization of physiological races and existence of both mating types in the field to pepper growers and breeders is discussed.     

Magnetic Field and Plasma Observations at Mars: Initial Results of the Mars Global Surveyor Mission

The magnetometer and electron reflectometer investigation (MAG/ER) on the Mars Global Surveyor spacecraft has obtained magnetic field and plasma observations throughout the near-Mars environment, from beyond the influence of Mars to just above the surface (at an altitude of approximately 100 kilometers). The solar wind interaction with Mars is in many ways similar to that at Venus and at an active comet, that is, primarily an ionospheric-atmospheric interaction. No significant planetary magnetic field of global scale has been detected to date (<2 x 10(21) Gauss-cubic centimeter), but here the discovery of multiple magnetic anomalies of small spatial scale in the crust of Mars is reported.     

Streptococcus suis serotypes associated with disease in weaned pigs

Streptococcus suis was recovered from 9 outbreaks of septicaemia and meningitis in weaned pigs between 1979 and 1983. Fifteen isolates from 7 outbreaks were identified as S. suis type 9, and 3 isolates from 2 outbreaks as S. suis type 2. Three further isolates of S. suis type 2 and an isolate of S. suis type 3 were recovered from cases of bronchopneumonia in weaned pigs from 4 other piggeries.     

Gram-negative bacterial infections and cardiovascular parasitism in green sea turtles (Chelonia mydas)

Objective To investigate causes of ill health and mortality in juvenile wild green sea turtles ( Chelonia mydas ) found along the mid-north west coast of Western Australia between June and October of 1997.
Procedure Department of Conservation and Land Management rangers submitted four dead or dying green sea turtles from separate incidents for veterinary examination, necropsy, and bacteriological, parasitological and histopatho-logical examination.
Results Numerous different species of trematodes belonging to the families Pronocephalidae, Microscaphidiidae and Paramphistomidae were detected in the intestines of two turtles examined, and in all turtles there was severe spirorchid fluke infection including Haemoxenicon sp, Amphiorchis sp and Hapalotrema sp. Histopathological examination demonstrated severe multifocal to diffuse granulomatous vasculitis, aggregations of spirorchid fluke eggs and microabscesses throughout various tissues including intestines, kidney, liver, lung and brain. Cultures and or histopathological examination demonstrated disseminated Gram-negative bacterial infections including salmonella, E coli , Citrobacter freundii and Moraxella sp.
Conclusion Infections caused by salmonellae, E coli and other Gram-negative bacteria should be considered as causes of systemic illness and death in wild green sea turtles infected with spirorchid cardiovascular flukes and other internal parasites.     

Effect of 16 and 24 hours daily radiation (light) on lettuce growth

A 50% increase in total radiation by extending the photoperiod from 16 to 24 hr doubled the weight of all cultivars of loose-leaf lettuce (Lactuca sativa L.) 'Grand Rapids Forcing', 'Waldmanns Green', 'Salad Bowl', and 'RubyConn', but not a Butterhead cultivar, 'Salina'. When total daily radiation (moles of photons) was the same, plants under continuous radiation weighed 30% to 50% more than plants under a 16 hr photoperiod. By using continuous radiation on loose-leaf lettuce, fewer lamp fixtures were required and yield was increased.