Description and life cycle of a new Physarum (Myxomycetes) from the Atacama Desert in Chile

A new species of Physarum (Myxomycetes), Physarum atacamense is described in this paper, and details are provided on its life cycle as observed in spore-to-spore culture in agar. The new species was collected during studies of the Atacama Desert in Chile. It has been collected directly in the field and isolated in moist chamber cultures prepared with material from an endemic cactus. The combination of characters that make this species unique in the genus are its large fusiform nodes of the capillitium, its long, bicolored stalk and the very dark brown and densely warted angular spores. The morphology of specimens of this myxomycete was examined with scanning electron microscopy and light microscopy, and micrographs of relevant details and life cycle stages are included in this paper. The importance of resistant stages in the life cycle of this myxomycete is stressed, and the close association of this myxomycete with its plant substrates is discussed.     

小绒泡菌生活史及其形态建成期显微结构的观察

在完成小绒泡菌Physcaum pusillum生活史的同时,观察了小绒泡菌P.pusillum生活史不同阶段显微结构的形成.生活史研究结果表明:小绒泡菌P.pusillum的孢子萌发方式为裂式,黏变形体具两根鞭毛,较短一根不易观察到,原质团类型为显型原质团,子实体形态建成过程约需12-13h.显微结构观察结果表明:石...     

扁绒泡菌的生活史

黏菌的生活史对于研究其营养方式的多样性以及系统发育等具有重要价值,目前国内外有关黏菌生活史的报导很少。利用燕麦-琼脂培养、基物培养及扫描电镜技术研究了扁绒泡菌的个体发育过程,在燕麦琼脂培养基上完成了从孢子到孢子的生活史。结果表明,扁绒泡菌生活史包括单核的黏变形体或游动胞、多核的营养体原质团以及孢子形成阶段。孢子球形,表面具细小疣点。孢子萌发为裂式,释放1黏变形体。原质团类型为显型。成熟原质团乳白色,可形成多个孢囊。琼脂培养基上获得的扁绒泡菌孢子与野生型相似,并具有可育性。     

Spore-to-spore agar culture of the myxomycete Physarum globuliferum

The ontogeny of the myxomycete Physarum globuliferum was observed on corn meal agar and hanging drop cultures without adding sterile oat flakes, bacteria or other microorganisms. Its complete life cycle including spore germination, myxamoebae, swarm cells, plasmodial development, and maturity of fructifications was demonstrated. Details of spore-to-spore development are described and illustrated.     

淡黄绒泡菌原质团的培养及其rDNA-ITS序列分析

首次实现了黏菌淡黄绒泡菌Physarum melleum原质团的燕麦琼脂培养,并通过ITS引物完成了淡黄绒泡菌rDNA的PCR扩增及序列分析。描述了其原质团的培养方法,提供了原质团rDNA的提取方法及ITS引物的扩增条件。利用邻近结合法构建系统发育树,对淡黄绒泡菌与相关分类单元的分子系统学关系进行了初步探讨。     

Description and culture of a new succulenticolous Didymium (Myxomycetes)

A new succulenticolous Myxomycete species, Didymium wildpretii, found on decaying remains of various species of cacti, is described from two arid zones of the world. This species was collected from central Mexico, at the southern limit of the Chihuahuan Desert, and from the Canary Islands (Spain). The new species has small, pale yellow sporocarps, 0.1-0.7 mm high, that are sessile or have short, orange-yellow, calcareous stalks and small, uniformly warted spores. The stability of the taxonomic characters of the species was confirmed with both moist chamber cultures and spore-to-spore culture on agar. Life cycle events are described from germination to sporulation. Myxomycete specimens were examined with scanning electron microscopy and light microscopy, and micrographs of relevant morphological details are included.     

Evolution of dark-spored Myxomycetes (slime-molds): molecules versus morphology

The Myxomycetes are a major component of soil amoebae, displaying a complex life cycle that terminates in the formation of often macroscopic fruiting bodies. The classification of Myxomycetes is controversial and strongly depends on the weight given by different authors to morphological and developmental characters. We used a molecular approach to establish the phylogenetic relationships in the dark-spored orders Stemonitales and Physarales. Twenty-five small subunit ribosomal RNA gene sequences were obtained, with focus on two Stemonitales genera, Lamproderma and Comatricha. Unexpectedly, our results show that Stemonitales are paraphyletic with Physarales arising from within a Lamproderma clade. The genus Lamproderma itself is polyphyletic and can be divided into two distinct clades. Additionally, we found that Comatricha nigricapillitia comprises two cryptic species, both related to Enerthenema. Our study allows the reappraisal of morphological and developmental characters in the light of molecular data and sets foundations for a new classification of Myxomycetes.     

灰绒泡菌生活史及其子实体发育过程的显微观察

为明确灰绒泡菌Physarum cinereum的个体发育特征,本研究在实验室条件下完成了该菌的生活史,并对其子实体发育过程进行显微观察。灰绒泡菌P. cinereum孢子萌发方式为裂式,显型原质团水白色;子实体形态建成可分为孢囊形成期和孢囊成熟期,孢囊成熟期幼孢囊颜色随着孢子的形成呈现白色-红棕色-黑褐色逐渐加深的变化;子实体在发育过程中孢丝形成后原生质割裂形成孢子。     

Life history of the oligochaete Enchytraeus coronatus (Annelida, Enchytraeidae) in agar culture

Abstract. Life-history attributes and the reproductive biology of Enchytraeus coronatus (Oligochaeta, Enchytraeidae) were studied in agar cultures, as a basis for using this species in toxicity tests and other experimental studies. The use of agar allows daily examination of the behavior, reproduction, and mortality of the worms. At 20°C, E. coronatus had a generation time of 21–22 days and an embryonic period of 7–10 days. Hatch rate was high (>80%) and worms became sexually mature 8–10 days after hatching. Cocoon production and number of eggs per cocoon were positively correlated. Mortality in the first stages of the life cycle (embryonic period and first week after hatching) was about 38%. Three different periods of cocoon production were distinguished: a period characterized by a regular increase in the number of cocoons produced (weeks 4–9), a period of production at a constant high rate of ∼5 cocoons per week (weeks 10–20), and a period of decline in production rate (weeks 21–32), down to a mean value of 1.6 cocoons per adult in the last week. This study showed that synchronized agar cultures of cohorts can provide adults for long-term experimental tests, with the age for optimum reproduction being 8–20 weeks.     

Life cycle ofCorophium insidiosum (Crustacea,Amphipoda) in laboratory culture

The life cycle ofCorophium insidiosum (Crawford) was investigated for the first time in laboratory cultures. This amphipod is mainly a suspension feeder, but it can also switch to deposit feeding. It was cultivated in standing, unaerated finger bowls, feeding on detritus, living or dried algal matter, rotifers (Brachionus plicatilis), or large-sized phytoplankton (e. g. the flagellateScrippsiella faeroense). A mixture of these items gave best results and hence was used for long-term cultivation. Preliminary results are presented on ingestion rate (suspension feeding), digestion rate, starvation resistance, and elemental and biochemical composition. In the life cycle ofC. insidiosum, several factors were found to play an important role: temperature, individual age, sex, and in contrast to other amphipod species thus far studied also the age of the mother animal at the time of breeding. Increasing temperature reduces the total life span, the age and size at the time of attaining sexual maturity, and the duration of marsupial development. It increases growth and moulting rate. At increasing individual age, the growth rate, and in males also the moulting rate, decrease, while the number of offspring per brood and surprisingly also the duration of its marsupial development increase. Females generally have a longer life span than males, and they show a higher number of moults, higher moulting frequency and growth rate, and a larger maximum body size. Body length and age at the time of reaching sexual maturity are smaller in males than in females. Furthermore the age of the mother animal at the time of breeding proved to be of particular importance: Individuals from early broods have an apparently longer life span than those originating from late broods, and they have more moults, mostly a higher growth rate, higher number of broods, higher total number of offspring, and, surprisingly, also a longer period of incubating their broods. These major factors have differing combined effects.     

Life cycle and morphology of Anisops sardeus Herrich-Schaeffer, 1849 (Heteroptera: Notonectidae)

The life cycle of Anisops sardeus was studied by rearing individuals from egg to adult stage in laboratory conditions at a water temperature of 23.2 ± 1.4 °C during the wet season (May-June) and 19 ± 1.8 °C during the dry season (December-February). The incubation period averaged 8 ± 0.8 and 11.5 ± 1.7 days during the wet and dry seasons, respectively. Duration of the five instars averaged 3.4 ± 0.5, 4.4 ± 0.5, 4.8 ± 0.8, 5 ± 0.7, and 6.9 ± 0.7 days, respectively during the wet season, and 4.9 ± 0.7, 6.5 ± 1.1, 7.5 ± 1.1, 8.1 ± 0.7, and 9.4 ± 1.1 days, respectively during the dry season. Total developmental time averaged 32.5 ± 2 and 47.9 ± 2.8 days in the wet and dry seasons, respectively. The average period of incubation and developmental time of the five instars were shorter in the wet season as compared to those in the dry season. But individuals were larger in the dry season. The variations in morphometric ratios of different characteristic features of laboratory reared specimens among different developmental stages in both the wet and dry seasons, and field collected specimens in the wet season were highly significant as revealed by one-way MANOVA (F = 95.45, p < 0.001; F = 124.38, p < 0.001; F = 5022.85, p < 0.001, respectively). Five instars are described in detail with emphasis on 29 morphometric ratios. This study discerned six morphometric ratios such as length of wing pad/ width of wing pad (WL/WW), length of wing pad/body length (WL/BL), length of head/length of body (HL/BL), length of meso femur/length of meso tibia (FE2L/TI2L), synthlipsis/width of head (S/HW), and vertex/synthlipsis (V/S) which can be used for discriminating instars I-V.     

Sterol content of the Myxomycetes Physarum polycephalum and P. flavicomum.

The sterol content of two Myxomycetes, Physarum polycephalum and P. flavicomum has been examined. The sterols of the two species are apparently identical, the two major sterols in each being poriferasterol and 22-dihydroporiferasterol. Threee minor sterols are probably delta5-ergostenol, ergostanol, and poriferastanol. The triterpenoids of the two species differ in that, though lanosterol was identified in both, 22-dihydrolanosterol was indicated only in P. flavicomum. The occurrence of lanosterol together with a typical mixture of plant sterols is somewhat unusual.     

黏菌生活周期不同阶段细胞核的观察

在显微和亚显微2个水平对黏菌孢子、原质团和菌核中细胞核进行了观察。试验结果表明,幼孢子中细胞核着色明显,原质团中细胞核在荧光染料染色的条件下易于被观察到,而菌核中的细胞核即使在电镜下也难以确定。     

Life cycle and morphology of Metagonimus miyatai (Digenea: Heterophyidae) from Nagano,Japan

The life cycle of Metagonimus miyatai Saito, Chai, Kim, Lee and Rim, 1997 (Digenea: Heterophyidae) was studied in the Hiroi River at Kotobuki, Iiyama City, Nagano Prefecture, central Japan. Daughter rediae and cercariae were found in Semisulcospira libertina (Gould) and S. dolorosa (Gould) (Gastropoda: Pleuroceridae). Metacercariae were found encysted in Phoxinus lagowskii steindachneri Sauvage (Osteichthyes: Cyprinidae). Cercariae were experimentally exposed to P. lagowskii steindachneri, and metacercariae were obtained from the fish. Metacercariae of natural and experimental infections were experimentally fed to respective golden hamsters, and gravid adults identifiable as M. miyatai were recovered from the small intestine of the golden hamsters. The daughter redia, cercaria, metacercariae and adults are described. The life cycle of M. miyatai is discussed.     

Life cycle and morphology ofMelampsora yezoensis onSalix serissaefolia

Uredinial and telial states of aMelampsora species occurring on the leaves ofSalix serissaefolia were for the first time recorded. Field observations and inoculation experiments showed that the spermogonial and aecial states of the fungus were formed onChelidonium majus var.asiaticum andCorydalis incisa. The fungus was identified asMelampsora yezoensis based on the morphological observation of all the spore states. Urediniospores were able to infectS. erocarpa andS. pierotii as well asS. serissaefolia andS. jessoensis. Salix serissaefolia, S. eriocarpa, andS. pierotii are new uredinial and telial hosts ofM. yezoensis, andC. majus var.asiaticum andC. incisa are new spermogonial and aecial hosts of the fungus. Contribution No. 124, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry University of Tsukuba.     

First report of sporangia of a myxomycete (Physarum pusillum) on the body of a living animal, the lizard Corytophanes cristatus

Myxomycetes are protists whose life cycle depends on aerially dispersed spores that germinate into motile myxamoebae, which then pair and fuse to form a larger, motile plasmodium. The plasmodium seeks out a suitable fruiting site (usually atop vegetative material or detritus) and transforms into fruiting bodies that release the spores. In this paper we report the first known instance of a myxomycete, in this case Physarum pusillum, sporulating on the body of a living animal, the cryptic lizard Corytophanes cristatus, which was collected in eastern Honduras in 2003.     

Morphological and molecular characterization of a new succulenticolous Physarum (Myxomycetes,Amoebozoa) with unique polygonal spores linked in chains

A new plasmodiocarpic and sporocarpic species of myxomycete in the genus Physarum is described and illustrated. This new species appeared on decayed leaves and remains of succulent plants (Agave, Opuntia, Yucca) growing in arid zones. It differs from all other species in the genus in having polyhedral spores linked in chains like a string of beads, a unique feature within all known myxomycetes. Apart from detailed morphological data, partial sequences of both the small-subunit ribosomal RNA and elongation factor 1-alpha genes, generated from four isolates collected in two distant regions, i.e., Mexico and Canary Islands, are also provided in this study. Combined evidence supports the identity of the specimens under study as a new species.     

蛹期薜荔榕小蜂的琼脂培养

[目的]薜荔Ficus pumila var.pumila瘦果具有极高的营养食用价值,其结实依赖薜荔榕小蜂Wiebesia pumilae传粉.本研究旨在探讨蛹期植食性寄生蜂室内培养的可能性.[方法]在不同温度(22,24,26,28,30和32℃)和光周期(0L∶24D,10L∶14D,12L∶12D,14L∶10D...