Amylolytic activity of Byssochlamys fulva

Byssochlamys fulva was found to produce a glucoamylase (EC 3.2.1.3) that exhibited its maximal activity at 50°C and had a broad optimum pH range of 4.0–5.2. The K_m and V_max values of the crude enzyme for amylopectin were 0.15% and 17.9 mg glucose l^-1 min-^-1, respectively. The molecular weight of the enzyme as estimated by the gel-filtration method was 34 kDa.     

Byssochlamyopeptidase A, a Rennin-like Enzyme Produced by Byssochlamys fulva

The production of a rennin-like enzyme by Byssochlamys fulva varied considerably with the isolates tested. Among the seven isolates tested, NRRL 2260, IMI 83277, and N.Y. 1 were good enzyme producers. The enzyme produced by isolate IMI 83277 was purified approximately 20-fold after (NH(4))(2)SO(4) precipitation, diethylaminoethyl-cellulose chromatography and Sephadex G-100 gel filtration. The partially purified enzyme has a pH optimum at 2.9 and a temperature optimum around 60 C. The enzyme appeared to be relatively stable at 40 C between pH 3.0 and pH 6.85. A name, byssochlamyopeptidase A, was proposed for this new enzyme. The milk-clotting activity of byssochlamyo-peptidase A is dependent on pH and appeared to be minimal at pH 6.2 or above. No extensive proteolysis has been observed during the milk-clotting process. The non-trichloroacetic acid-precipitable nitrogen titration curve on skim milk was comparable to that catalyzed by animal rennet.     

Byssotoxin A, a secondary metabolite of Byssochlamys fulva.

Byssochlamys fulva, isolated from corn, was grown on nutrient-amended shredded wheat medium for 14 days at 25 C. Crude solvent extract from these cultures was toxic to brine shrimp, chicken embryos, and rats. The extract was slightly inhibitory to the germination of of pea seeds, but was nontoxic to ten species of bacteria and one of yeast. One metabolite was isolated, given the trivial name byssotoxin A, and partially characterized chemically and physically.     

Production of polygalacturonase byByssochlamys fulva

Summary Byssochlamys fulva was grown in two fermentation media using shake flasks, stirred fermentor and disc fermentor under conditions to give maximum production of pectolytic enzymes. Only polygalacturonase activity was detected in the culture filtrates during all fermentations. In all production conditions studied, no evidence of pectin methylesterase, pectin lyase, cellulase or proteinase activities were found. The maximum polygalacturonase activity (4.5 units/ml) was achieved when the microorganism was grown on medium II in shake flasks at pH 4.0–4.5 and 30°C after 12 days of fermentation.     

番茄叶霉病菌ISSR-PCR体系的建立

以番茄叶霉病菌(Passalora fulva)基因组DNA为模板,采用单因素试验和正交设计试验对该菌ISSR-PCR体系中的一些重要参数(Mg2+、dNTPs、引物、模板DNA、TaqDNA聚合酶、缓冲液、循环次数)和引物进行筛选和优化,并对退火温度进行了梯度优化,建立了番茄叶霉病菌ISSR-PCR的最佳反应体系(20μL):Mg2+1.5 mmol/L,dNTPs 0.4 mmol/L,引物1.5μmol/L,模板DNA45 ng,TaqDNA聚合酶1.0 U,1倍的PCR缓冲液,循环40次,退火温度50℃。     

The ultra-structure of spores of Byssochlamys fulva

The ultra-structures of conidio- and ascospores of the ascomyceteByssochlamys fulva have been investigated in the electron microscope by means of ultrathin sections embedded in Vestopal and in Epon 812. The structure of conidiospores is completely different from that of ascospores. The most striking difference is the formation of extremely thick intermediate space between the cellwall and the cytoplasmic membrane of the ascospores. Within the intermediate space another cell-layer could be detected which might represent an additional protection for the cytoplasm against external influences.

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Zusammenfassung Die Ultrastrukturen der Konidio- und Askosporen der AskomyzetenByssochlamys fulva sind im Elektronmikroskop mittels ultradünner Schnitte, eingebettet in Vestopal und in Epon 812, untersucht worden. Die Struktur der Konidiosporen ist von denen der Askosporen völlig verschieden. Der auffallendste Unterschied ist die Bildung eines äußerst dicken Zwischenraumes zwischen der Zellwand und der zytoplasmatischen Membrane der Askosporen. Innerhalb des Zwischenraumes war eine andere Zellenschicht sichtbar, die wohl einen zusätzlichen Schutz des Zytoplasmas gegen äußere Einwirkung darstellen mag.

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This work was supported by grant FG-Austria-102 from the United States Department of Agriculture.     

Colony size, reproductive success, and colony choice in Cave Swallows Petrochelidon fulva

We investigated how annual reproductive success, as measured by the number of nestlings surviving to day 10 and the percentage of nests that were successful, varied with colony size of the Cave Swallow Petrochelidon fulva in south central Texas. We also studied whether Cave Swallows chose colonies, in part, on the basis of reproductive success at a site the previous year. Neither measure of reproductive success varied significantly with colony size for either first-wave or second-wave nestings. Mean clutch size per colony did not vary significantly with colony size. Mean nestling body mass, an index of parental foraging efficiency, was unrelated to colony size, except for broods of five, in which nestling mass declined significantly with colony size. Colony size was not significantly affected by reproductive success at the site the previous year, although sites with more successful nests during the first wave declined less in size during the second wave within the same season than did sites that had fewer successful first-wave nests. Unlike the closely related Cliff Swallow Petrochelidon pyrrhonota , Cave Swallows did not use breeding performance of conspecifics in choosing nest-sites, because they did not preferentially aggregate at sites that were the most successful the previous year. Coloniality in Cave Swallows did not appear to have a net negative effect on annual fitness, suggesting that colonial nesting was not solely a response to nest-site limitation, but the benefits of breeding colonially (if any) were unclear.     

Eimeria dispersa and Eimeria gallopavonis: Infectivity, Survival, and Development in Primary Chicken and Turkey Kidney Cell Cultures

SYNOPSIS. Eimeria dispersa (turkey strain) and Eimeria gallopavonis sporozoites were inoculated into primary cultures of chicken kidney (CK) and turkey kidney (TK) cells. Eimeria dispersa sporozoites were more infective in either cell type than those of E. gallopavonis : at 4 hr, the percentage of infection was 67-98 for E. dispersa but only 23-56 for E. gallopavonis . E. dispersa also survived better in culture: at 2 days, losses of E. dispersa in both cell types were only 4-19%, whereas losses of E. gallopavonis were 35-47% in TK cells and 60–95% in CK cells. However, E. gallopavonis developed further than E. dispersa . Location and increase in numbers of intracellular stages at 4 days indicated that E. dispersa proceeded through 2 schizogonic generations before development stopped.     

Speciation studies with Eimeria acervulina and Eimeria mivati.

Eimeria mivati was described as a new species of chicken coccidia in 1964 by Edgar and Seibold, but recently some British workers have relegated its status to that of a variety of Eimeria acervulina. Using strains supplied by Dr. Edgar, we have prepared lines of E. acervulina resistant to methyl benzoquate, sulfaquinoxaline and robenidine and a line of E. mivati resistant to methyl benzoquate. Genetic transfer of resistance between the various lines of E. acervulina to produce doubly-resistant coccidia has been demonstrated, but no such transfer could be obtained between E. mivati resistant to methyl benzoquate and the resistant lines of E. acervulina. Although some immunological relationship between E. acervulina and E. mivati has been demonstrated, we conclude that this failure of the 2 organisms to interbreed lends support to the status of E. mivati as a distinct species.     

Cytokines, free radicals and resistance to Eimeria

The cytokine, gamma-interferon (IFN-gamma), which is produced by CD4(+) T cells, plays a crucial role in host resistance to Eimeria infections. Karen Ovington and Nick Smith propose that free oxygen radical generation by leukocytes in response to infection with Eimeria is the result of activation by IFN-gamma. The functional role of free oxygen radicals is unclear but these highly reactive radicals are produced by the leukocytes that infiltrate the intestine in large numbers during infection, and the parasites,enterocytes and cells of the immune system may all be vulnerable to oxidative damage. Gamma-interferon also appears to induce the enterocytes inhabited by Eimeria to turn against the parasite. The authors draw from literature documenting similar effects on other protozoa, especially Leishmania and Plasmodium, and speculate that reactive nitrogen intermediates produced by enterocytes have a functional role in resistance to Eimeria.     

Excystation of the Poultry Coccidium, Eimeria acervulina

SYNOPSIS. Using intervals up to 5 hours, attempts to excyst sporozoites of Eimeria acervulina from intact oocysts in vitro were unsuccessful.
Examination of crop, gizzard, and intestinal contents of chicks fed large numbers of sporulated oocysts indicated that (1) no obvious change in the oocysts occurred in the crop, (2) a high percentage of the sporocysts were quickly released from the oocysts in the gizzard, (3) the sporozoites escaped from the liberated sporocysts in the duodenum and jejunum, and (4) the action of the digestive juice was apparently on the sporocysts rather than on the oocysts.
In vitro attempts to excyst sporozoites from free sporocysts with various pancreatic preparations in the absence of bile produced low or insignificant percentages of excystation. In the presence of bile, bile salts, and other surface-active agents, the action of the pancreatic preparations was greatly increased. The heaviest suspension of motile, nonaggregating sporozoites was obtained with 0.25% trypsin 1–300 in 5% chicken bile at pH 7.6.     

Genotoxic evaluation of extracts from Aplysina fulva, a Brazilian marine sponge

A range of biologically active secondary metabolites with pharmacological application has been reported to occur in marine sponges. The present study was undertaken to provide a set of data on the safety of a hydro-alcoholic extract (ALE) and an aqueous fraction (AQE) from Aplysina fulva Pallas, 1766 (Aplysinidae, Verongida, Porifera). Salmonella typhimurium strains TA97, TA98, TA100 and TA102, Escherichia coli strains PQ65, OG40, OG100, PQ35 and PQ37 and Balb/c 3T3 mouse fibroblasts were used to detect induction of DNA lesions by ALE and AQE. Assays used for these analyses were a bacterial (reverse) mutation assay (Ames test), the SOS-chromotest and the comet assay. Both extracts presented identical infrared 2-oxazolidone spectra. ALE treatment induced a higher frequency of type-4 comets, indicative of increasing DNA migration, in the alkaline comet assay. ALE also induced a weak genotoxic effect, as expressed by the induction factor (IF) values in the test with E. coli strain PQ35 (IF=1.5) and by cytotoxic effects in strains PQ35, PQ65 and PQ37. Positive SOS induction (IF=1.7) was detected in strain PQ37 treated with diluted AQE. No genotoxic effects were observed in strains PQ35, PQ65, OG40 and OG 100 after treatment with AQE dilutions. Using the bacterial (reverse) mutation test and survival assays with or without S9 mix, after 60min of pre-incubation, we observed for strain TA97 treated with ALE a weak mutagenic response (MI=2.2), while cytotoxic effects were seen for strains TA98, TA100 and TA102. AQE did not show mutagenic activity in any of the strains tested, but a weak cytotoxic effect was noted in strain TA102. Our data suggest that both ALE and AQE from A. fulva induce DNA breaks leading to cytotoxicity and mutagenicity under the conditions used.     

Eimeria clethrionomysis sp. n., Eimeria gallatii sp. n., Eimeria pileata sp. n. and Eimeria marconii sp. n. from the red-backed vole Clethrionomys gapperi Vigors, from Pennsylvania.

Four new eimerian species are described from red-backed voles, Clethrionomys gapperi in Pennsylvania. Sporulated oocysts of Eimeria clethrionomyis sp. n. are ellipsoidal, 18.8 (16.5-21.5) x 14.9 (14.0-16.5) with elongate, ovoid sporocysts, 10.6 (9.5-12.0) x6.1 (5.5-7.0). The oocyst wall is smooth, with 2 layers, and thins, with terminal cap at one or both ends. Polar granules, dark Stieda body and sporocyst residuum are present. The oocyst residuum is absent. Sporulated oocysts of Eimeria gallatii sp. n. are ellipsoidal, 27.7 (21-32) x 19.3 (17-24) with ovoid sporocysts, 13.5 (12-15) x 8.8 (8-10). The oocyst wall is smooth, 2-layered, with a micropyle and thin wall at the end opposite the micropyle. Polar granules, Stieda body and sporocyst residuum are present. The oocyst residuum is atypical, of cobwebby material. Sporulated oocysts of Eimeria pileata sp. n. are subspherical to spherical, 25.2 (20.5-29.5) x 22.5 (19.5-25.5) with ellipsoidal sporocysts, 13.4(10.5-15.0) x 8.4 (7.5-9.5). The oocyst wall is rough, pitted, striated, 2-layered, with no micropyle. Polar granules, oocyst and sporocyst residuum, Stieda body and stiedal cap are present. Sporulated oocysts of Eimeria marconii sp. n. are ellipsoidal, 13.0 (10.5-15-0) x 10.6 (9.5-12.0) with elongate, ovoid sporocysts, 7.7 (7.0-8.5) x 4.2 (3.0-4.5). The oocyst wall is smooth, single-layered, with no micropyle. Polar granules, dark Stiedal body and sporocyst residuum are present. There is no oocyst residuum.