Contaminant loads and hematological correlates in the harbor seal (Phoca vitulina) of San Francisco Bay, California.

An expanding body of research indicates that exposure to contaminants may impact marine mammal health, thus possibly contributing to population declines. The harbor seal population of the San Francisco Bay (SFB), California, has suffered habitat loss and degradation, including decades of environmental contamination. To explore the possibility of contaminant-induced health alterations in this population, blood levels of polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and polybrominated diphenyl ethers (PBDEs) were quantified in free-ranging seals; relationships between contaminant exposure and several key hematological parameters were examined; and PCB levels in the present study were compared with levels determined in SFB seals a decade earlier. PCB residues in harbor seal blood decreased during the past decade, but remained at levels great enough that adverse reproductive and immunological effects might be expected. Main results included a positive association between leukocyte counts and PBDEs, PCBs, and DDE in seals, and an inverse relationship between red blood cell count and PBDEs. Although not necessarily pathologic, these responses may serve as sentinel indications of contaminant-induced alterations in harbor seals of SFB, which, in individuals with relatively high contaminant burdens, might include increased rates of infection and anemia.

[A conbribution to the characterization of asparagus virus 2 (author's transl)]. / Ein Beitrag zur Charakterisierung des Spargel-Virus 2.

In host range investigations with 152 plant species of 37 families, 96 species from 28 families proved to be experimentally susceptible to asparagus virus 2 (AsV 2). From these, 82 species of 26 families were systematically infectible and 14 species of 10 families only locally. Most frequently were symptomless systemic infections. Of 86 species, their susceptibility for AsV 2 was unknown before. The number of families that contant experimental hosts of the virus increased from 11 to 33. Transmission of AsV 2 was neither possible with Myzus persicae nor with Cuscuta californica or C. campestris. AsV 2-infected mother plants transmitted the virus by about 40 per cent to their seedings. Open-pollinated plants, not infested by AsV 2, showed 3 to 22 per cent of infected seedings. Mechanical back-transmission of AsV 2 from test plants to asparagus succeeded only in one case. The properties of the virus in vitro were as follows: thermal inactivation point between 64 and 66 degrees C, dilution end point between 10(-3) and 10(-4), stability in sap, stored at room temperature, up to 96 hours. Serological investigations demonstrated no relationship to the virus to numerous other viruses. An antiserum with a titer of 1 to 16 was useful for the detection of AvV 2 in asparagus sap. Electron microscopical investigations proved for the virus isometric particles for the first time. In negatively stained preparations they had a diameter of 27 nm.

[Spontaneous hosts of broad bean wilt virus. Communication]. / Spontane Wirtspflanzen des Ackerbohnenwelke-Virus. 2. Mitteilung.

Of 110 plant species, grown from seeds in the vicinity of sources of broad bean wilt virus (BBWV) in 1974, exactly 50% proved to be infected by the mentioned virus within one vegetation period. Obviously 54 of the species are previously unknown hosts of BBWV. They belong to the following 21 families: Amaranthaceae, Boraginaceae, Campanulaceae, Caryophyllaceae, Chenopodiaceae, Commelinaceae, Compositae, Cruciferae, Euphorbiaceae, Hydrophyllaceae, Labiatae, Leguminosae, Loasaceae, Papaveraceae, Polemoniaceae, Portulacaceae, Ranunculaceae, Resedaceae, Scrophulariaceae, Solanaceae, and Umbelliferae. Within 6 families, marked by, no spontaneous hosts of BBWV were ascertained before. Only a few of the plant species found to be infected did not show disease symptoms. However, a considerable part of the BBWV hosts were additionally infected by cucumber mosaic virus. BBWV seems to possess a natural host range not very much less than alfalfa mosaic virus. Among monocotyls BBWV seems to have even a larger host range than alfalaf mosaic virus has.

[Laboratory and field tests about the transmission of Erysimum latent virus by Phyllotreata species (Chrsomelidae) (author's transl)]. / Labor- und Freilandversuche zur Ubertragung des latenten Erysimum-Virus durch Phyllotreta-Arten (Chrysomelidae).

Erysimum latent virus (ELV) proved to be transmissible by Phyllotreta atra, P. nemorum, P. nigripes, and P. undulata. From them P. nemorum is a new discovered vector. The acquisition of the virus by the beetles was possible within a feeding time of less than 10 minutes. Because virus transmission could be performed within 30 to 60 minutes immediately after virus uptake there exists apparently no latent period in the vector. The retention or persistence of ELV in the Phyllotreta species amounted up to 3 days. Trials to induce infectivity of Phyllotreta species by injection of the virus were unsuccessful. ELV was transmissible by Aphis frangulae gossypii, Brevicoryne brassicae, and Myzus persicae neither in short nor in long feeding times. Field tests showed that the Phyllotreta species are able to spread ELV under natural conditions.

[Virus infestation of garden radish (Raphanus sativus L. var. sativus) (author's transl)]. / Virusbefall am Radies (Raphanus sativus L. var. sativus)

In July 1974 a mosaic disease was stated in seed plants of garden radish near Aschersleben which spread more and more within some weeks and eventually infected over 40 per cent of the stand. Investigations in comparison with healthy seed plants demonstrated the following average losses induced by the disease: number of pods 51 per cent, seed weight 67 per cent, number of seeds per plant 53 per cent, weight of 1,000 seeds 33 per cent. Nearly unaffected were: number of seeds per pod, percentage of seed germination, and percentage of emerged seedlings. However, the seedlings were smaller when they derived from diseased mother plants. From diseased seed plants cauliflower mosaic virus was isolated. Seed transmission of this virus could not be stated with several hundreds of seedlings deriving from diseased garden radish. Back transmissions were successful with sap and with aphids. Only one strain which was cultivated in greenhouse for a long time gave no positive results. Three isolates of cabbage black ring virus from different plant species and the four beetle-transmissible viruses, namely turnip yellow mosaic, turnip crinkle, turnip rosette, and radish mosaic viruses induced no symptoms on garden radish seedlings. However, Erysimum latent virus, also belonging to the beetle-transmissible viruses, sometimes caused symptoms in garden radish. For the first time the investigations demonstrated in Europe, but probably also for the other continents, a spontaneous virus infection of Raphanus sativus var. sativus.