Induction of Accelerated Sporangial Lysis by Basic Peptide Antibiotics. A Novel Method of Preparation of Free Spores of Bacilli

An accelerated release of free spores from sporangia of Bacillus cereus NCIB-8122 and Bacillus subtilis SMYW was induced by the addition of the basic peptide antibiotics, polymyxin B or colistin (100 μg/ml), to sporangia formed in liquid Bactopeptone medium. Destruction of sporangial cell walls of B. cereus prelabelled with ³H-4-diaminopimelic acid commenced shortly after the addition of either antibiotic, the label being gradually released into the medium. Normal free spores were released following the addition of antibiotics to sporangia containing refractile spores (stages IV-V of sporogenesis). Earlier additions induced the lysis of both compartments of the sporangium, accompanied by the release of already-synthesized dipicolinic acid and alreadyaccumulated ⁴⁵calcium. The heat resistance and germination ability of spores released in the presence of the antibiotics were the same as those of control spores released by long-term spontaneous lysis of sporangia. Similar effects of the antibiotics were observed with B. subtilis SMYW. Results obtained were used firstly for fast preparation of relatively clean free spores and secondly for the characterization of the developmental stage of sporogenesis at which the spore becomes independent of the maternal cell. It reaches this property at the end of stage IV and during stage V.     

Strong resistance to potato tuber necrotic ringspot disease in potato induced by transformation with coat protein gene sequences from an NTN isolate of Potato virus Y

The potato cv. Igor is susceptible to infection with Potato virus Y (PVY) and in Slovenia it has been so severely affected with NTN isolates of PVY causing potato tuber necrotic ringspot disease (PTNRD) that its cultivation has ceased. Plants of cv. Igor were transformed with two transgenes that contained coat protein gene sequence of PVY^NTN. Both transgenes used PVY sequence in a sense (+) orientation, one in native translational context (N‐CP), and one with a frame‐shift mutation (FS‐CP). Although most transgenic lines were susceptible to infection with PVY^NTN and PVY^O, several lines showed resistance that could be classified into two types. Following manual or graft inoculation, plants of partially resistant lines developed some symptoms in foliage and tubers, and virus titre in the foliage, estimated by ELISA, was low or undetectable. In highly resistant (R) lines, symptoms did not develop in foliage and on tubers, and virus could not be detected in foliage by ELISA or infectivity assay. Four lines from 34 tested (two N‐CP and two FS‐CP) were R to PVY^NTN and PVY^O and one additional line was R to PVY^O. When cv. Spey was transformed with the same constructs, they did not confer strong resistance to PVY^O.     

On the identity of turmeric: the typification of Curcuma longa L. (Zingiberaceae)

Although Curcuma L. (Zingiberaceae) is a conserved name, with C. longa L. as its conserved type, the type of C. longa is still uncertain. Numerous discussions about the identity of the taxon called C. longa by Linnaeus have been followed by various attempts to rename turmeric, suggestions as how to settle the type and proposals to conserve the name from a later author in order to stabilize the situation. Unfortunately, none of the previous proposals can be upheld for reasons which are discussed in this article. A lectotype is selected from extant material examined by Linnaeus and an epitype collected near the type locality is designated here. The identity of C. longa is discussed and a colour plate of the species is included. Synonyms of C. longa and their types are discussed and notes on the variability of C. longa are provided.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 37–46.     

Influence of floral resources on sugar feeding and nutrient dynamics of a parasitoid in the field

Abstract.  1. To investigate how floral resources impact feeding and nutrient dynamics of parasitoids, the ichneumonid Diadegma insulare (Cresson) was monitored in cabbage fields with and without buckwheat Fagopyrum esculentum Moench borders. Biochemical analyses of field-collected wasps determined whether sugar feeding occurred, and whether it enhanced nutrient levels and increased parasitism of diamondback larvae Plutella xylostella (L.) from 2000 to 2003. The effects of experimental spatial scale on sugar feeding dynamics were also evaluated in 2001.
2. The majority of D. insulare foraging on cabbage had fed upon sugar, but floral borders did not consistently increase the proportion of sugar-fed wasps or their levels of glycogen and lipid over all 4 years. Floral borders increased sugar storage by females in 2001. More females fed on sugar when experimental plots were separated by at least 800 m compared with 67 m.
3. Feeding on buckwheat nectar vs. honeydew produced by the soybean aphid Aphis glycines Matsumura in surrounding fields was distinguished using the ratio of fructose to total sugars, which was higher in nectar- than in honeydew-fed parasitoids. Floral borders increased the probability that females collected from adjacent crops were nectar-fed in 2002, demonstrating that floral resources were utilised by foraging parasitoids. Diadegma insulare that fed upon any sugar source had higher levels of sugar and glycogen than unfed wasps, and feeding on honeydew appeared to enhance nutrient storage.
4. The prevalence of sugar or nectar feeding by female D. insulare was not correlated with parasitism rates over the 4 years from all plots, but nectar feeding was positively correlated with parasitism rates within floral plots.     

THE DEVELOPMENT OF THE LUDLOVIAN GRAPTOLITE SAETOGRAPTUS VARIANS

The Ludlovian graptolite Saetograptus varians (Wood 1900) has been isolated from a limestone matrix. The thecal structure indicates that the species is closer to the genus Saetograptus Přibyl 1942, emend. Urbanek 1958, than to Colonograptus Přibyl 1942, emend. Urbanek 1958; but it requires that the definition of the former be amended to include Colonograptus as a junior synonym.     

EFFECT OF DIFFERENT MOLLUSC ASSOCIATIONS ON TARGET MOLLUSC GROWTH AND PARASITE CERCARIAL PRODUCTION IN THE TRIPLE SYSTEM: BULINUS WRIGHTI-SCHISTOSOMA BOVIS AND MELANOPSIS PRAEMORSA

The influence of different mollusc associations in the triplesystem: Bulinus wrighti (target mollusc: TM)—Schistosomabovis (parasite)—Melanopsis praemorsa (non-target mollusc:NTM) is analysed. The results show that: (i) for a TM/NTM densityratio of 1/1, the NTM stimulates both growth of the TM and parasitecercarial production; (ii) for a TM/NTM density ratio of 1/5,the effects of the NTM on TM growth and cercarial productionwere not additive and were less marked than for the 1/1 ratio.Hypotheses on a chemical explanation for these density-dependenteffects are discussed. (Received 30 December 1991; accepted 9 March 1992)