Egg Morphology Research Articles

Baylisascaris schroederi Infection in Giant Pandas (Ailuropoda melanoleuca) in Foping National Nature Reserve, China.

The giant panda (Ailuropoda melanoleuca) is the most iconic endangered species in the world, but there is little information about the spatial and temporal distribution of parasites in the wild giant panda population. In total, 193 fecal samples from giant pandas in the Foping National Nature Reserve, People's Republic of China, were analyzed for parasite eggs using a modification of the McMaster technique. The morphology and size of Baylisascaris schroederi eggs were observed under an optical microscope. The prevalence and intensity of B. schroederi infection during the sampling year 2012 were 52.3% (101/193) and 89 eggs/g of feces, respectively, among giant pandas in this population. The prevalence of B. schroederi in the pandas varied during different months of the year, from 7% to 100%, and the prevalences in spring, summer, autumn, and winter were 71, 77, 23, and 18%, respectively. The prevalence was not significantly different between giant pandas that ate two different types of bamboo, but the intensity of infection was higher in the group eating Arundinaria fargesii (P=0.043). Altitude, temperature, and dew point were correlated with the infection intensity (r=-0.224, P<0.001; r=0.328, P<0.001; r=0.328, P=0.028, respectively). There was no correlation between infection intensity and distance to rivers. This study provides a better understanding of B. schroederi prevalence among the wild giant pandas in Foping National Nature, China.

A revision of the clam shrimp Australimnadia Timms and Schwentner, 2012 (Crustacea: Spinicaudata: Limnadiidae) with two new species from Western Australia

The original type species of Australimnadia is made a junior synonym of A. grobbeni, originally described as Limnadia grobbeni Daday, 1925. A second species of Australimnadia is described from Onslow, Western Australia; it differs in having unique egg morphology and is distinct in many morphological characters, including those of the telson and cercopod, but also of the thoracopods. Its validity is confirmed by molecular differences between the two species in COI and EF1α. A third species from southwestern Western Australia is separated morphologically by unique spination of the telson and setation of the cercopod, and by its egg morphology.

Ultrastructure of the eggs of four species of Culicoides Latreille (Diptera: Ceratopogonidae) with a key to the eggs of all studied species by SEM

The ultrastructure of eggs of Culicoides anophelis Edwards, C. fulvus Sen and Das Gupta, and C. huffi Causey are described along with a re-description of C. oxystoma Kieffer based on scanning electron micrographs (SEM). The importance of the distribution and abundance of ansulae in species recognition is demonstrated by compiling the morphology of all species for which data is available for a key to species based on egg morphology. No correlation between egg morphology and phylogenetic placement of species was found although some association between morphology and egg habitat was noted.

First Egg and Standardized Nest Description of the Southern Bristle-Tyrant (Phylloscartes eximius)

ABSTRACT In spite of its relevance, data on nest architecture and egg morphology are lacking for several bird species, especially in the Neotropics. We provide the first egg and standardized nest description of the Southern Bristle-Tyrant (Phylloscartes eximius), a species considered in the genus Pogonotriccus by some authors. Similarly to two other studies, the nest was a closed/globular/lateral structure built mostly with moss and spider web. The only egg we found was clean white and measured 17.1 mm length x 13.5 mm width. Given the plasticity of nest building and the low sample size, more nests should be described to infer relatedness among Phylloscartes and Pogonotriccus using nest architecture. Similarly, more eggs of these species should be described.

Reproduction Cycle of the Eastern Egg-Eater Snake Dasypeltis medici medici (Bianconi, 1859) in Captivity

For the first time the data on the complete reproductive cycle of the eastern egg-eater snake ( Dasypeltis medici medici ) have been documented and recorded. The data, collected from specimens in captivity, illustrate the age when they reach sexual maturity, mating and its frequency in the course of the year, gestation, clutch size, egg morphology, incubation times as well as different results based on the parameters used, appearance and general characteristics of the hatchlings.

Reproduction Cycle of the Eastern Egg-Eater Snake &lt;i&gt;Dasypeltis medici medici&lt;/i&gt; (Bianconi, 1859) in Captivity

For the first time the data on the complete reproductive cycle of the eastern egg-eater snake ( Dasypeltis medici medici ) have been documented and recorded. The data, collected from specimens in captivity, illustrate the age when they reach sexual maturity, mating and its frequency in the course of the year, gestation, clutch size, egg morphology, incubation times as well as different results based on the parameters used, appearance and general characteristics of the hatchlings.

A new Indian record and morphological variation for Eulimnadia khoratensis Rogers et al., 2016 (Crustacea: Branchiopoda: Spinicaudata).

Eulimnadia Packard, 1874 is the most species rich and widely distributed genus within the Limnadiidae (Reed et al. 2015). Species identification relies primarily on egg morphology as adult morphological characters show high variability, sometimes within the same populations and hence of little use (Rabet, 2010; Rogers et al. 2012). Seven species are currently known from the Indian subcontinent (sensu Rogers & Padhye 2015) and SE Asia (Rogers et al. 2016). Of these, four species, viz. E. compressa (Baird, 1860), E. michaeli Nayar & Nair, 1968 and E. indocylindrova Durga Prasad and Simhachalam, 2004, E. azisi Babu and Nandan, 2010 are known from peninsular India (Padhye et al. 2015; Rogers & Padhye, 2015), although, much of this region remains unstudied (Padhye pers. obs.). With this background, we present a new Indian record of E. khoratensis Rogers, Dadseepai and Sanoamuang, 2016 from the Western region of Maharashtra state, India, extending its distribution a few thousand kilometers westwards.

Egg identification of three economical important fish species using DNA barcoding in comparison to a morphological determination

Accurate identification of fish eggs to species level is a challenging task as many species have similar egg sizes and morphology. The results of egg determination of three economically important fish species are presented by using DNA barcoding in comparison to the classical morphological determination. About 500 fish eggs from the Celtic Sea were collected, morphologically identified and used for DNA analysis. In total, DNA barcodes were successfully obtained from 98% of the investigated eggs, including 167 DNA barcodes from 169 morphologically identified fish eggs of Merluccius merluccius (98.8%), 257 of 262 Scomber scombrus (98.1%), and 47 from 50 Trachurus trachurus (94%). Overall, species identification with DNA barcodes showed a congruence of 96.2% to identification by morphology, whereas 3.8% (n = 18) of the analyzed eggs were morphologically assigned to the wrong species. The highest number of incorrect identified eggs was for S. scombrus (n = 15). Our study highlights the usefulness of DNA barcoding for valid fish egg identification but also indicates the robustness of the classical morphology-based approach.

Improvement of a tissue maceration technique for the determination of placental involvement in schistosomiasis.

Schistosomiasis in pregnancy may cause low birth weight, prematurity and stillbirth of the offspring. The placenta of pregnant women might be involved when schistosome ova are trapped in placental tissue. Standard histopathological methods only allow the examination of a limited amount of placental tissue and are therefore not sufficiently sensitive. Thus, placental schistosomiasis remains underdiagnosed and its role in contributing to schistosomiasis-associated pregnancy outcomes remains unclear. Here we investigated an advanced maceration method in order to recover a maximum number of schistosome ova from the placenta. We examined the effect of different potassium hydroxide (KOH) concentrations and different tissue fixatives with respect to maceration success and egg morphology. Placental tissue was kept either in 0.9% saline, 5% formalin or 70% ethanol and was macerated together with Schistosoma mansoni infested mouse livers and KOH 4% or 10%, respectively. We found that placenta maceration using 4% KOH at 37°C for 24 h was the most effective method: placental tissue was completely digested, egg morphology was well preserved and alkaline concentration was the lowest. Ethanol proved to be the best fixative for this method. Here we propose an improved maceration technique in terms of sensitivity, safety and required skills, which may enable its wider use also in endemic areas. This technique may contribute to clarifying the role of placental involvement in pregnant women with schistosomiasis.

Clinical diagnostic value of viable Schistosoma japonicum eggs detected in host tissues

BackgroundSchistosomiasis, one of the neglected tropical diseases, is endemic in more than 70 countries. However, the clinical diagnosis of patients with a low degree of infection is an unsolved technical problem. In areas endemic for schistosomiasis japonica, proctoscopy detection of eggs has been one method used for clinical diagnosis. However, it is often a challenge to find typical live eggs and it is difficult to distinguish live eggs from large numbers of partially degraded and/or completely degraded eggs within colon biopsy tissue. To address this problem, we tested six different morphological and biochemical/molecular markers (ALP; morphological characteristics of egg; CalS (calcified substance); AOS (antioxidase); SDHG (succinic dehydrogenase) and SjR2 mRNA (retrotransposons 2 of S.japonicum genome mRNA)), including four new markers (CalS; AOS; SDHG and SjR2 mRNA.), to determine the viability of S. japonicum eggs deposited in human and mouse colon tissues. Our ultimate aim is to obtain a new method that is more sensitive, practical and accurate to clinically diagnose schistosomiasis.MethodsTissue samples were collected from mice at six different time points during S. japonicum infection with or without treatment with praziquantel (PZQ). Four new biochemical or molecular markers were used for the detection of egg viability from mouse liver and intestinal samples: CalS; AOS; SDHG and SjR2 mRNA. Subsequently, all markers were employed for the detection and analysis of eggs deposited in biopsy materials from patients with suspected schistosomiasis japonica for clinical evaluation. Microscopic examination of the egg morphology, worm burden in vivo and ALP (alkaline phosphatase) levels were used as a reference standard to evaluate the sensitivity and reliability of four new markers detecting egg viability.ResultsThe results of the study showed that the morphology of S. japonicum eggs deposited in tissues of hosts with schistosomiasis, especially cases with chronic schistosomiasis, is complex and egg viability is difficult to judge morphologically, particularly eggs with a fuzzy structure or partially modified eggs. We found that the majority of the viable schistosome eggs determined by four new markers (CalS, AOS, SDHG and SjR2 mRNA) were morphologically difficult to identify.ConclusionsAmong the markers, the most sensitive and specific method was the detection of SjR2 mRNA and the most simple, rapid and practical method was the detection of SDHG. Therefore, the detection of SDHG is the most practical for clinical application and its use could improve the accuracy in diagnosing active schistosome infection.

Ultrastructural morphology of the envelope of Dover sole Solea solea eggs from fertilization until hatching with emphasis on sample preparation

This study is the first to describe the ultrastructural morphology of the envelope of Solea solea eggs from fertilisation until hatching. Defining the ultrastructural morphology of fish eggs is important for species identification and may assist in predicting the effect of external influences on these early life stages. In first instance, various fixation and embedding protocols were assessed to explore the morphology of the egg envelope, whereby the encountered difficulties were highlighted. The successful protocol for SEM proved to be combined fixation with 4% glutaraldehyde in 0.1M cacodylate buffer for minimum 4h with post-fixation of 2h with 1% OsO4 in 0.1M cacodylate buffer. For TEM, puncturing the egg envelope during the first steps of the fixation protocol was necessary to allow the embedding medium to penetrate through the egg envelope. Based on both scanning and transmission electron microscopical examination, three distinct layers were discerned in the egg envelope. During the development of the fish embryo, a change in the outer structure of the egg was observed. Scanning electron microscopical examination of one day post-fertilisation eggs (DPF) revealed a homogeneous outer layer, displaying a large number of pores uniformly distributed on the surface of the egg envelope. Starting from 2 DPF parts of the outermost layer or two outer layers peeled off. The second deeper layer showed larger pores, with less defined edges. In the third innermost layer irregular indentations were noted. On transmission electron microscopy the first outermost layer of 1 DPF eggs clearly folded into the pores. The second layer was more electron dense, had a uniform appearance and did not cover the surface of the pores. The third innermost layer was much thicker and possessed indentations. A total number of 12 undulating zones were discriminated based on different degrees of electron density. Prior to hatching, the compact structure of the innermost layer was distorted by dispersed holes and tears.

Integrative taxonomic revision of Campylocia (mayflies: Ephemeroptera, Euthyplociidae)

A morphological comparison of type and non-type material of species of Campylocia, including their junior synonyms, was conducted, in addition to neighbour joining based on K2P distances and Bayesian inference analyses of 376 bp of the mitochondrial gene cytochrome oxidase I (COI) of recently collected specimens. Results revealed the lack of distinguishing characters between C. bocainensis and C. dochmia supported by the molecular analysis, where the overlap of intra- and interspecific genetic divergences suggested genetic flow among individuals. Campylocia burmeisteri is revalidated as a senior synonym of Brazilian south-eastern species C. bocainensis and C. dochmia and of E. guntheri, formerly a synonym of C. anceps. Campylocia burmeisteri is redescribed based on material from its type-locality, Nova Friburgo, Rio de Janeiro State. Two new species, C. demoulini sp. nov. and C. araca sp. nov., are described from the Amazon rain forest and a third species, C. orosi sp. nov., is described from Costa Rica. Possible cryptic species and the utility of egg morphology in the taxonomy of Campylocia are discussed for the first time for the genus. A key to the identification of adult stages of Campylocia is provided based on male genitalia and egg morphologyhttp://zoobank.org/urn:lsid:zoobank.org:pub:6779DC2C-DB98-41DF-8C52-FF97366AAF7A

Detecting hybridization in African schistosome species: does egg morphology complement molecular species identification?

Hybrid parasites may have an increased transmission potential and higher virulence compared to their parental species. Consequently, hybrid detection is critical for disease control. Previous crossing experiments showed that hybrid schistosome eggs have distinct morphotypes. We therefore compared the performance of egg morphology with molecular markers with regard to detecting hybridization in schistosomes. We studied the morphology of 303 terminal-spined eggs, originating from 19 individuals inhabiting a hybrid zone with natural crosses between the human parasite Schistosoma haematobium and the livestock parasite Schistosoma bovis in Senegal. The egg sizes showed a high variability and ranged between 92·4 and 176·4 µm in length and between 35·7 and 93·0 µm in width. No distinct morphotypes were found and all eggs resembled, to varying extent, the typical S. haematobium egg type. However, molecular analyses on the same eggs clearly showed the presence of two distinct partial mitochondrial cox1 profiles, namely S. bovis and S. haematobium, and only a single nuclear ITS rDNA profile (S. haematobium). Therefore, in these particular crosses, egg morphology appears not a good indicator of hybrid ancestry. We conclude by discussing strengths and limitations of molecular methods to detect hybrids in the context of high-throughput screening of field samples.

Beauty in the breakdown: The morphology of the first polar body in mature mouse eggs

In vitro maturation (IVM) is the process whereby oocytes arrested in prophase of meiosis I are stimulated to resume meiosis and progress to metaphase of meiosis II (MII) ex vivo. Here we examined the cytoskeletal morphology of mature MII eggs obtained following IVM. Cumulus oocyte complexes were isolated from antral follicles of hyper-stimulated female mice, and cumulus cells were removed to induce spontaneous oocyte meiotic maturation. This article is protected by copyright. All rights reserved

Comparative study of fertilization rates of C57BL/6NKorl and C57BL/6N mice obtained from two other sources

C57BL/6N is the most widely used inbred mouse strain applied in a wide variety of research areas including cancer, cardiovascular biology, developmental biology, diabetes and obesity, genetics, immunology, neurobiology, and sensorineural research. To compare the fertilization rates of C57BL/6NKorl mice with two commercial C57BL/6N stocks, differences in reproductive organ structures, sperm and egg numbers, fertilization rates, and embryo development rates among C57BL/6NKorl (Korea FDA source), C57BL/6NA (USA source), and C57BL/6NB (Japan source) mice were determined. Among the stocks, no significant differences were detected in organ weight and histological structure of male and female reproductive organs, although body weight was higher in C57BL/6NKorl mice than that in the other groups. The concentration and morphology of sperm and eggs in C57BL/6NKorl mice were similar to those of C57BL/6NA and C57BL/6NB mice. Furthermore, the three stocks had similar in vitro fertilization and embryo development rates, although these rates tended to be higher in C57BL/6NB mice. Pup body weight was higher in C57BL/6NKorl and C57BL/6NB mice than that in C57BL/6NA mice. The results of the present study suggest that C57BL/6NKorl, C57BL/6NA, and C57BL/6NB mice obtained from three different sources have similar fertilization and embryo development rates, although there were slight differences in the magnitude of their responses rates.

Morphology of the Resting Eggs of the Australian endemic Fairy Shrimp Australobranchipus (Branchiopoda: Anostraca: Branchipodidae): Similarities and differences from other anostracans

Eggs in large Branchiopoda are often diagnostic of species and may show some phyletic relationships. Those of the two species of Australobranchipus are described and are easily separable from each other and are particularly distinctive among Australian anostracans, all unrelated. Within its family, the Branchiopodidae however, there is some similarity to two African genera, but not Eurasian species, indicative perhaps of a gondwanan connection.

Incompatibility between mitochondrial and nuclear genomes during oogenesis results in ovarian failure and embryonic lethality.

Mitochondrial dysfunction can cause female infertility. An important unresolved issue is the extent to which incompatibility between mitochondrial and nuclear genomes contributes to female infertility. It has previously been shown that a mitochondrial haplotype from D. simulans (simw501 ) is incompatible with a nuclear genome from the D. melanogaster strain Oregon-R (OreR), resulting in impaired development, which was enhanced at higher temperature. This mito-nuclear incompatibility is between alleles of the nuclear-encoded mitochondrial tyrosyl-tRNA synthetase (Aatm) and the mitochondrial-encoded tyrosyl-tRNA that it aminoacylates. Here, we show that this mito-nuclear incompatibility causes a severe temperature-sensitive female infertility. The OreR nuclear genome contributed to death of ovarian germline stem cells and reduced egg production, which was further enhanced by the incompatibility with simw501 mitochondria. Mito-nuclear incompatibility also resulted in aberrant egg morphology and a maternal-effect on embryonic chromosome segregation and survival, which was completely dependent on the temperature and mito-nuclear genotype of the mother. Our findings show that maternal mito-nuclear incompatibility during Drosophila oogenesis has severe consequences for egg production and embryonic survival, with important broader relevance to human female infertility and mitochondrial replacement therapy.

The Effectiveness of Egg Morphology for Detecting Parasitized Nests and Eggs for Common Coots (Fulica atra) in Heilongjiang, China

Abstract. Identifying parasitized nests and eggs is a prerequisite for studying conspecific brood parasitism. Previous studies on the effectiveness of egg morphology to identify parasitic eggs of different species have produced mixed results. Brood parasitism and egg measurements (length, width and weight) were monitored in Common Coot (Fulica atra; n = 85) nests. Maximum Euclidean distance was calculated for each nest. Results indicated that maximum Euclidean distance values of non-parasitized and parasitized nests were significantly different (t83 = 9.747, P < 0.01). The optimal split value of recursive partitioning analysis for Common Coot nests was 2.98 (R2 = 0.65), which can identify 93.3% non-parasitized and 88.0% parasitized nests successfully. However the most dissimilar egg in parasitized nests calculated by maximum average Euclidean distance only identified 39.3% of the parasitic eggs correctly. Egg morphology is effective for detecting conspecific brood parasitism of Common Coot nests, but is n...

Review of the Eulimnadia (Branchiopoda: Spinicaudata: Limnadiidae) from Argentina with the description of a new species.

A new spinicaudatan species, Eulimnadia pampa sp. nov., is described from Argentina mostly based on the differential egg morphology. This species was collected from rainwater pools from Buenos Aires City and the provinces of Buenos Aires and Entre Ríos, and compared to other Neotropical species. Previous Argentine record of E. brasiliensis is shown to belong to our new species, which represents the southernmost Neotropical Eulimnadia. We also present new records of the Paraguayan Eulimnadia ovisimilis Martin and Belk, 1989 from northeastern Argentina. Eulimnadia santiaguensis is treated as a species inquirenda, thus we recognize only three Eulimnadia species in Argentina: E. pampa sp. nov., E. ovilunata and E. ovisimilis, and we provide a brief indentification key. We present the first description and SEM images of the putative Eulimnadia spermatophore, which we found in the new species.

Reproductive trade-off of the copepod Acartia tonsa in a hypersaline estuary of the Southwestern Atlantic. Temporal variations in the morphology of eggs

ABSTRACTThe purpose of the present work was to study the seasonal variations in egg production, morphology and hatching success in the cryptic species Acartia tonsa, taking into account variations in female size, population abundance and environmental factors in a turbid and hypersaline estuary. Sampling was performed during the austral warm (18–23°C and 32–36 salinity) and cold seasons (5–7°C; 32–38) in Bahía Blanca Estuary (BBE), Argentina, during 2007 and 2009. Field-collected females were incubated in the laboratory simulating in situ environmental conditions, and specimens from fixed samples were measured using optical and scanning electronic microscopy. Acartia tonsa’s marked seasonality in its reproductive traits was found to ensure its permanence in the water column all over the year. During the warm season, small-sized females were observed to invest their energy in the production of subitaneous eggs with high hatching success and smooth appearance (12.95 ± 2.38 eggs f−1 day−1 and specific egg production rate (SEP) of 16.57%C f−1 day−1). During the cold season, females invested C in body mass as well as in the production of resting eggs of three different morphotypes (6.56 ± 3.2 eggs f−1 day−1 and SEP of 7.37%C f−1 day−1). Although these morphotypes were found to show differences in surface ornamentation, they exhibited the same delayed hatching behaviour. The eggs with shorter spines were found to integrate the resting egg bank in BBE. Our findings confirming a delayed egg hatching behaviour and a great tolerance to low temperatures and high salinities in the A. tonsa population in BBE suggest that this possible strain is a valuable phenotype for aquaculture.