Studies on Streptomycetes

Investigation was made on the mycological properties of a strain No. 45449 isolated from a sample of soil collected in Fukuchiyama. Since the antibiotics produced by the strain resembled hydroxymycin and paromomycin, the strain was compared with the hydroxymycin and paromomycin-producing strains, S. paucisporogenes and S. rimosus forma paromomycinus, and as a result the strain No. 45449 was found to be different from the latter two strains. Among known strains, S. flavogriseus resembles the present strain, but they are different morphologically and in the kind of the antibiotics they produce. Thus, as the strain No. 45449 was found to be a new strain, it was named S. pulveraceus nov. sp. The antibiotics produced by the present strain are physiologically basic substances active against Gram-positive and negative bacteria and acid fast bacteria, and they are considered to belong to the neomycin-kanamycin group.     

Host population structure affects field sex ratios of the heteronomous hyperparasitoid, Coccophagus atratus

Abstract.

• 1 Second instar Filippia gemina de Lotto scale insects are the preferred hosts of female Coccophugus atrutus Compere larvae. These scale insects were found on their host plants, Chrysanthemoides monilifera Norlindh and Cliffortia strobilifera Mettenius, only at certain times during a 1 year sampling programme.
• 2 Late larval instars and prepupae of C.atratus, and a Metaphycus species, are the preferred hosts of male C.atratus larvae. These hosts, although they occurred on the same host plants as hosts for female C.atratus, were most numerous at different times during the sampling period.
• 3 The ratio of hosts suitable for C.atratus varied from a predominance of hosts suitable for females through to a predominance of hosts suitable for males. Sex ratios of adult C.atratus followed a similar trend but did not reflect, exactly, the ratio of available hosts. Differences in mortality between sexes and hyperparasitism may account for this anomaly.
• 4 Variable population sex ratios observed in C.atratus apparently result from the behaviour of individual females in which brood sex ratios are dependent on the relative availability of hosts for males and hosts for females. This behaviour, in turn, may result from variability in the host population structure but may also result from selection pressures operating at the time that heteronomous hyperparasitism evolved.

     

Two imide substances from a soil-isolated Streptomyces atratus strain provide effective biocontrol activity against grapevine downy mildew

Grapevine downy mildew (Plasmopara viticola) is a devastating disease of grapevine. In this study, 151 actinomycete isolates were obtained and tested for antagonistic activity against P. viticola. The assay suggested that 28 isolates displayed antagonistic effects to varying degrees. The greatest reduction in disease severity was observed with isolate PY-1, which reduced disease severity by 92.13% in the detached leaf assay, and by 83% in a field assay. It was identified as Streptomyces atratus using the 16S rDNA sequence analysis. To elucidate the antagonistic mechanism of PY-1 against P. viticola, scanning electron microscopy showed that major damage to the pathogens sporangia and sporangiophores was observed after treatment for PY-1. Furthermore, PY-1 showed antagonistic activity against other pathogens, including: Botrytis cinerea, Colletotrichum orbiculare, Fusarium oxysporum, Phytophthora capsici and Phytophthora infestans. Two imide compounds were purified from the fermentation liquid using silica gel chromatography and high-performance liquid chromatography and identified as 5-acetoxycycloheximide and cycloheximide using nuclear magnetic resonance. Both compounds showed significant antagonistic activity against P. viticola, determining a reduction in disease severity by 65% and 84%, respectively. In conclusion, 5-acetoxycycloheximide and cycloheximide were identified for the first time in a new S. atratus strain able to effectively control grapevine downy mildew.     

大麦虫及其肠道微生物对聚乙烯的生物降解

【背景】废旧塑料聚乙烯因具有较高的化学惰性,不易被自然降解而形成长期污染。【目的】探究聚乙烯泡沫塑料对大麦虫生长发育的影响,为大麦虫作为降解聚乙烯泡沫塑料的昆虫推广提供理论依据。【方法】以大麦虫幼虫为研究对象,选用常见的泡沫塑料(聚乙烯),采用4种不同的饲喂方式T1 (麦麸)、T2 (泡沫塑料)、T3 (泡沫塑料+麦麸)、T4 (不饲喂)进行驯化,处理30 d后对大麦虫进行解剖,取肠道内容物于LB培养基中进行富集培养,将富集培养后的菌液加入以聚乙烯(polyethylene,PE)为唯一碳源的LCFBM培养基进行选择性培养,从中筛选分离得到对PE塑料有降解能力的菌株。【结果】取食泡沫塑料30d后,与单一饲喂PE相比,麦麸和PE混合饲喂后大麦虫幼虫的存活率为76%。采用傅里叶变换红外光谱检测发现虫粪组分中主要官能团中峰值明显变化,表明PE长链有断裂现象,并从肠道中分离得到3株可以对PE薄膜边缘造成明显侵蚀的菌株。【结论】大麦虫可取食并消化PE塑料,其肠道内的微生物对PE塑料的降解起到关键作用,研究结果为塑料污染的生物降解提供了科学证据。     

A mucous secretion in the malpighian tubes of a neotropical bumblebee,Bombus atratus Franklin

Summary A filamentous secretion composed of carboxylated and sulfated acid glycosaminoglycans (AGAG), neutral polysaccharides, and protein(s) appears in the lumen of the Malpighian tubes of the fully grown larvae of the bumblebee,Bombus atratus Franklin. A well-ordered macromolecular array was demonstrated specially for the carboxylated AGAG components of this secretion, based on their linear dichroism and birefringence properties. It is suggested that the carboxylated AGAG macromolecules can acquire a helical conformation when present at the lumen of the organ. The mucous secretion elaborated by the Malpighian tubes ofB. atratus is excreted from the larvae in the form of condensed filaments. Its function remains unclear. Globules with concentric lamination containing protein and neutral polysaccharides were seen detaching from the apical border of the epithelial cells of the Malpighian tubes of the fully grown larvae. It could not be established whether they contribute for the elaboration of the filamentous secretion. Morphologically similar globules have been assumed in some other insect groups to originate from cytolysomes. Urate crystals surrounded by a halo of calcium granules were also found in the lumen of the Malpighian tubes ofB. atratus.     

Microbiological Studies on a New Species of Oospora,Oospora astringenes nov. sp.

Investigation was made on the mycological properties of a species of Oospora which was isolated from the air of bronchial asthma patient’s room, Tokyo, Japan.

This species was considered to be a new one and named as Oospora astringenes nov. sp. On the malt extract glucose agar at room temperature, the colonies appear velvety, powdery and white. Conidia are ellipsoidal or cylindrical, mostly 7.0×4.3 µ in size, hyaline.

This new species utilizes only organic compounds as a sole source of nitrogen and its growth is markedly stimulated by the addition of some vitamins.     

New physiological activities of myosuppressin,sulfakinin and NVP-like peptide in <Emphasis Type="Italic">Zophobas atratus</Emphasis> beetle

Three neuropeptides Zopat-MS-2 (pEDVDHVFLRFa), Zopat-SK-1 (pETSDDYGHLRFa) and Zopat-NVPL-4trunc. (GRWGGFA), recently isolated from the neuroendocrine system of the Zophobas atratus beetle, were tested for their myotropic and hyperglycaemic activities in this species. These peptides exerted differentiated dose-dependent and tissue specific physiological effects. Zopat-MS-2 inhibited contractions of the isolated heart, ejaculatory duct, oviduct and hindgut of adult beetles and induced bimodal effects in the heart contractile activity of pupae in vivo. It also increased the haemolymph free sugar level in larvae of this species, apart from myotropic activity. Zopat-SK-1 showed myostimulatory action on the isolated hindgut of the adult beetles, but it decreased contractions of the heart, ejaculatory duct and oviduct. Injections of this peptide at a dose of 2 μg also caused delayed cardioinhibitory effects on the heartbeat of the pupae. Together with the ability to increase free sugar level in the haemolymph of larvae these were new physiological activities of sulfakinins in insects. Zopat-NVPL-4trunc. inhibited the muscle contractions of the two organs: hindgut and ejaculatory duct but it was inactive on the oviduct and the heart of the adult beetles. This peptide also increased free sugar level concentration in the haemolymph of Z. atratus larvae. These physiological actions are the first biological activities discovered for this group of the insect peptides. The present work showed pleiotropic activity of three neuropeptides and indicates that the visceral muscle contractions and the haemolymph sugar homeostasis in Z. atratus are regulated by complex mechanisms.     

Increasing distribution and damage to palms by the Neotropical whitefly,Aleurotrachelus atratus (Hemiptera: Aleyrodidae)

In recent years, the coconut whitefly, Aleurotrachelus atratus Hempel, has been recorded from various islands in the southwestern Indian Ocean. Field surveys in La Réunion, the Seychelles, the Comoros and glasshouses in Paris have allowed us to record this whitefly on 56 palm species, some of which are endemic and/or threatened species. Most of trees showed low infestation levels, except for the coconut palm that is its main host plant. Such a wide host range has facilitated the rapid geographical dissemination of this whitefly. A field study was conducted in 2006 in La Réunion, to gain a better understanding of the bioecology of A. atratus in a tropical insular ecosystem. The whitefly was found throughout the island, from sea level to 800‐m altitude. Five parasitoid species (Hymenoptera: Aphelinidae) were found associated with the populations of this pest, with Eretmocerus cocois Delvare being the dominant one. A laboratory study showed that the pre‐imaginal development of A. atratus is around 48 days at 25–27°C, which is relatively long compared to other whitefly species. With a sex ratio of one male per 1022 females collected in La Réunion, it appears that the whitefly reproduces by thelytoky. It represents a threat to ornamental and agricultural palms as well as to natural palm ecosystems in the absence of effective parasitoids.     

Bacteria present in the gut of two neotropicalCephalotini ants,Cephalotes atratus andZacryptocerus cf.pusillus

Insects have varied patterns of gut design and some of them allow the establishment of a fermentative microflora. Anaerobically cultured digestive bacteria fromCephalotes atratus andZacryptocerus cf.pusillus were counted, isolated and characterized. Individuals from both species had a density of 10⁵ bacteria per gram of digestive organ (ventriculum, ileum and rectum). Bacterial strains were mostly facultative anaerobes and H₂S producers, and had no cellulolytic nor uric acid degrading activities. Primary mixed cultures from the gut ofC. atratus had wider tolerance to pH and temperature variations than Z. cf.pusillus, which was consistent with characteristics regarding its digestive microbial composition and its habitat.     

Studies on Xylanase from Microorganisms

As xylanase-producing microorganisms, 64 strains belonging to the genus Streptomyces were isolated from the barn-yard manures, silages and litters collected in Hokkaido district. Among these isolates the strain 102–1–4, which was found to be a new species under taxonomical studies and named Streptomyces xylophagus nov. sp., had the most outstanding ability for the enzyme production. In addition to the isolates, 38 strains of Streptomyces and 480 strains of filamentous fungi which have been preserved in our culture collection were also examined on their ability to produce the enzyme. 1) Among the strains of Streptomyces tested, only two strains, St. albogriseolus IAM 0031 and St. olivaceus IAM 0025 were found to have the ability, but their abilities were less than that of St. xylophagus nov. sp. 2) Out of 480 strains of fungi tested, Chaetomium, Schyzophyllum, Trametes, Echinodontium, Alternaria, Cepharosporium, Cercospora, Gibberella, Glomerella and Macrosporium produced the enzyme. Especially, Ch. trilateral 2264 was the most excellent.     

Cardioactive properties of Solanaceae plant extracts and pure glycoalkaloids on Zophobas atratus

Glycoalkaloids, the biologically active secondary metabolites produced by Solanaceae plants, are natural defenses against animals, insects and fungi. In this paper, the effects of glycoalkaloids present in extracts of Solanaceae plants (potato, tomato and black nightshade) or pure commercial glycoalkaloids on the coleopteran Zophobas atratus F. were evaluated by in vitro and in vivo bioassays using heart experimental models. Each tested extract induced a dose‐dependent cardioinhibitory effect. The perfusion of Zophobas atratus semi‐isolated heart using the highest potato and tomato extract concentration (1 mmol/L) caused irreversible cardiac arrests, while extract from black nightshade produced fast but reversible arrests. Pure commercial glycoalkaloids caused similar but less evident effects compared with extracts. Our results showed that the bioactivity of tested compounds depended on their structure and suggested the existence of synergistic interactions when combinations of the main glycoalkaloids of potato and black nightshade were used for trials. Surprisingly, injection of tomato and potato extracts in 1‐day‐old pupae of Zophobas atratus induced reversible positive chronotropic effects and decreased the duration of the both phases (anterograde and retrograde) of the heart contractile activity. Furthermore, these extracts affected the amplitude of the heart contractions.     

Brood sex ratios of the solitary parasitoid wasp, Coccophagus atratus

Abstract.

• 1 Female eggs of Coccophagus atratus are deposited within the haemolymph of coccoid scale insects. Male eggs are deposited on to late larval and prepupal stages of parasitoids of scale insects, including conspecifics.
• 2 When presented with either one host type or a combination of both host types, female C.atratus deposit all their available eggs, assigning the appropriate sex egg to each host encountered. Brood sizes are not adjusted for different combinations of hosts.
• 3 Behavioural observations show that females do not move away from patches of hosts until all their eggs are laid, regardless of the host type.
• 4 Brood sex ratios varied with changes in the relative availability of hosts for males and hosts for females. When both host-types were present in equal numbers, male biased sex ratios resulted (mean ±SEM =0.71 ± 0.009) and when 70% of hosts provided were suitable for female eggs, mostly female-biased sex ratios resulted (mean ± SEM = 0.37±0.01).
• 5 Our results do not fit predictions based on the assumption that a sex ratio of 0.5 should be expected in C.atratus. Observed sex ratios indicate that the unusual life histories of these parasitoids need to be taken into account in explanations of their sex ratios.

     

Morphological and molecular characteristics of selected species of Minidiscus (Bacillariophyta,Thalassiosiraceae)

We report on taxonomically distinguishing morphological features of six diatom taxa from the marine, nanoplanktonic genus, Minidiscus, found in Eastern Canada and neighbouring waters. Four of the six were also investigated using genetic approaches. We found that the culture deposited in the Provasoli-Guillard National Center for Culture of Marine Phytoplankton (CCMP) as CCMP 496 was morphologically closest to the published type image of M. trioculatus, whereas other isolates were morphologically and/or genetically divergent. Consequently, we propose three new taxa. One monoclonal line isolated from the Bay of Fundy is proposed as a new variety, M. trioculatus var. monoculatus. The well-studied nanoplanktonic diatom strain, CCMP 495, currently considered to be ‘M. trioculatus’ was morphologically and genetically divergent from CCMP 496 and we propose specific status for it, M. variabilis. We isolated a new strain from the Gulf of St Lawrence that was nearly genetically identical in 18S and ITS regions to CCMP 495, but showed distinct morphological differences and we propose a new form for this strain. Culture-based data were supplemented by those from natural seawater whenever possible. Two species (M. comicus, M. chilensis) known from our region, but unavailable in culture, are presented for comparison.     

Treatment of deep mycoses with itraconazole

Four patients with deep mycoses were treated with itraconazole. Two patients had chromoblastomycosis, one patient each had aspergillosis and Rhinofacial zygomycosis. These patients were either resistant to or showed poor response to Amphotericin B and/or ketoconazole. After the initial clinical and mycological evaluation, itraconazole was given in a daily dose of 200 mg orally. All patients responded to the drug very well. No adverse effects attributable to itraconazole were detected.     

Composition of the cell wall of the phage resistant mutantRhodopseudomonas capsulata St. Louis RC1-

A mutant ofRhodopseudomonas capsulata St. Louis (R. capsulata St. Louis RC1^-), resistant against the bacteriophage RC1, was isolated and its cytoplasmic membrane and cell wall fractions (buoyant densities on sucrose density gradient centrifugation: 1.123 and 1.222 g/cm³, respectively) were obtained. Different from the wild type strain, the cell wall fraction of the mutant lacked galactose. Galactose is a characteristic component of the capsule polysaccharide ofR. capsulata St. Louis. There were no differences in lipopolysaccharide and peptidoglycan compositions as well as in polypeptide patterns of the cell wall fractions between mutant and wild-type cells. Thus, the lack of a firmly bound capsule inR. capsulata St. Louis RC1^- was the only difference found.     

Molecular cloning,structural analysis,and the developmental expression of vitellogenin in the giant mealworm Zophobas atratus

The giant mealworm Zophobas atratus, which is used for commercial purposes, was officially introduced to Korea. However, physiological information of oocyte maturation for the mass rearing of Z. atratus has not been investigated. Here, we cloned Z. atratus vitellogenin (ZaVg) cDNA and analyzed the expression profiles during development to better understand oocyte maturation in Z. atratus. A multi-alignment and phylogenetic analysis using the deduced amino acids of ZaVg and those of other insect vitellogenins showed that ZaVg has typical Coleopteran Vg features. Consistent with ovarian development, lower expression levels of ZaVg protein in the fat body, hemolymph, and ovary were observed at 0 and 10 days in the adult stage, while higher expression levels of that were detected at 20, 30, and 40 days in the adult stage. These results suggest that the expression level of ZaVg is adult-stage specific, which providing basic information on Vg and oocyte development in Z. atratus.     

The Structure of a New Piperidine Derivative from Buckwheat Seeds (Fagopyrum esculentum Moench)

Streptomyces hygroscopicus No. B–5050-HA, which produces a mixture of six maridomycins, yielded a mutant which produced 75% of the mixture as maridomycin III (MDM III).

Growth of S. hygroscopicus No. B–5050-HA, an improved MDM producer, was almost completely inhibited by 20 µg/ml of valine. This inhibition was counteracted by the addition of isoleucine, threonine, homoserine, methionine, α-amino-n-butyrate and α-ketobutyrate.

A valine resistant mutant, strain AV was isolated and found to produce increased level of MDM III at the expense of other maridomycins. Production of MDM III by the parent strain depended on the addition of isoleucine to the medium, but that by this mutant did not.

The properties of strain AV were discussed.     

The impact of flooding and drought on seeds of Cnidium dubium, Gratiola officinalis, and Juncus atratus, three endangered perennial river corridor plants of Central European lowlands

The effects of flooding and drought on the post-flooding survival and germinability of seeds in the soil were investigated for three endangered river corridor angiosperms Cnidium dubium (Schkuhr) Thell., Gratiola officinalis L. and Juncus atratus Krocker. Freshly matured seeds were placed in small nylon bags and were buried in pots filled with soil collected from a wetland along the Lower Havel River. The pots were subjected to different winter/spring flooding treatments (30, 60, 120, and 180 days) and to drought for up to 3 years. Every year in spring, after drawdown, the seeds were exhumed, counted and tested for germination. Seed mortality of flooded seeds was low, except for C. dubium. Flooding did not affect germination of seeds of J. atratus. Flooding of seeds of C. dubium and G. officinalis had inconsistent, but no beneficial effects on germination of either. The year of harvest and the interannual variability of weather are found to be the main factors affecting germinability of C. dubium and G. officinalis in the course of the three consecutive years.The experiment showed that the capacity of the flooded seed bank to maintain germination ability and viability for extended periods of time could be directly related to the flooding duration of natural habitats of the three species. The three species are resilient to variable flooding. Seeds appeared desiccation tolerant, and single flooding events do not deplete their seed bank.     

Properties, relationships and transmission of a strain of raspberry ringspot virus infecting raspberry cultivars immune to the common Scottish strain*

Plants of Lloyd George and Seedling M raspberry (Rubus idaeus L.) were found in eastern Scotland infected with raspberry ringspot (RRV), a virus to which these varieties were previously considered immune. Most RRV isolates from affected plants caused milder symptoms in herbaceous test plants than did the type isolates of the common Scottish and English strains. In graft-transmission tests the Lloyd George strain of RRV infected all the raspberry cultivars tested, including those immune to the common Scottish strain. No consistent differences were found between isolates of the two strains in in vitro properties or serological behaviour. Both strains were transmitted in seed of Stellaria media and in soil containing Longidorus elongatus. Possible reasons why the new strain is uncommon in Scotland are discussed.     

A new Papulaspora species from the infected eye of a horse: Papulaspora equi sp. nov.

An unusual fungus, probably traumatically introduced into the eye of a horse while grazing, was studied on various mycological media. Upon examination of colonies the organism produced bulbils and clearly exhibited the characteristics of a new species of Papulaspora, P. equi Shadomy & Dixon.