Distribution and Tidal Rhythmicity of a Littoral Amphipod

The larval stages of the red mangrove crab Sesarma meinerti de Man were reared in the laboratory. Larval development consists of five zoeal stages and one megalopa. Zoeal development lasts an average of 25 days at 25°C. The external morphology of larvae is described in detail and their relationship with larvae of congeneric species is briefly discussed.     

A Comparative,Quantitative Study of the Micro-Arthropods in Different Types of Pasture Soil

The osmoregulatory abilities of the grapsoid crabs Cyclograpsus punctata*, Sesarma catenata andSesarma eulimene were studied comparatively in an attempt to explain, at least in part, their distribution in estuaries. Both survival and haemorymph osmotic pressure were used as indices of hyperosmotic regulatory ability.

All three species were shown to be capable of regulating their haemorymph osmotic pressure against lowered external salinities. S. eulimene was found to be better able to control its haemorymph concentration in very low salinities than S. catenata, which would account for the former's occurrence in the upper reaches of estuaries. C.punctatus was shown to be capable of roaintaining its haemorymph osmotic pressure above that of the environmental medium in lowered salinities, but without the degree of constancy characteristic of the two Sesarma species. It does, however, show a marked ability to tolerate lowered internal osmotic pressure, an ability which appears to develop in response to partial dilution of the haemorymph. These adaptations, together with its semi-terrestrial habit as a shore crab, suffice to enable C. punctata* to penetrate an estuary to almost the same extent as S. catenata.     

Tidal exchange of two decapod larvae Palaemon pacificus (Caridea) and Upogebia africana (Thalassinidae) between the Swartkops River estuary and adjacent coastal waters

Two 24-h plankton and seine-netting studies were carried out in the Swartkops estuary mouth, one during a spring-tide, the other on a neap-tide in order to determine larval movements of the prawns Palaemon pacificus and Upogebia africana in and out of the estuary. Two size classes of the former were caught, namely zoea 6 and adults. No zoeae 1, 2, 3, 4 or 5, post-larvae or juveniles were caught. Zoea 1 of U. africana are flushed out of the estuary into Algoa Bay on the nocturnal ebb-tide with very few returning on the subsequent flood-tide. Net fluxes were 97,1% and 99,9%. Larval life is then spent at sea after which the pre-postlarvae invade the estuary to reach the estuarine nursery areas. For P. pacificus this was during zoea 6, mainly on the nocturnal flood-tides. Net fluxes of P. pacificus zoea 6 were 95,8% and 100%. Most larval movement occurred at peak velocities as they utilize the tidal currents in dispersion and recruitment. Some P. pacificus zoea 6 are washed out again on ebb-tides, but lateral movement to the banks during slack-tide appears to be a mechanism to prevent this occurring. P. pacificus adult movement in the mouth region was better cor-related with nocturnal activity than with tidal movements.     

Early development and larval behaviour of a minnow,Barbus anoplus (Pisces: Cyprinidae)

The chubbyhead barb, Barbus anoplus, underwent a population explosion in the early phases of filling of Lake be Roux on the Orange River. This successful colonization was possibly related to the survival strategy of the young stages of this minnow. It is suggested that some of the development traits of B. anoplus enabled it to become the most widespread freshwater fish species south of the Limpopo River. The development and behaviour of embryos and larvae of B. anoplus are described and discussed with reference to their survival strategy and potential colonizing ability. Some of the protolarvae were pelagic and the relevance of this behaviour is noted.     

Observations on the life-cycles and larval morphogenesis of Haemonchus bedfordi,Impalaia tuberculoid and Longistrongylus sabie (Nematoda: Trichostrongyloidea) parasitic in impala,Aepyceros melampus

The previously unknown life-cycles of Haemonchus bedfordi, Impalala tuberculata and Longistrongylus sabie parasitic in impala, are recorded. Observations on the morphology of the developmental stages and their habitat of these three nematode species are described. The similarities and differences to closely related species or subspecies are discussed.The morphology of the developmental stages of Haemonchus bedfordi are compared to the Haemonchus spp., H. contortus and H. placei.     

Larval development of Spondyliosoma emarginatimi (Cuvier & Valenciennes) (Pisces: Sparidae) from southern Africa

The larval development of the southern African endemic sparid Spondyliosoma emarginatum is described and illustrated from specimens collected in Algoa Bay and the Swartkops, Sundays and Swartvlei estuaries of the Cape Province. S. emarginatum has demersal eggs. Preflexion larvae are moderately elongate (BD = 18–23% BL) with body depth increasing to 31 % BL in postflexion stages. The head is rounded and the snout blunt but becomes more elongate in postflexion stages. There are short spines on the preoperculum. Flexion occurs at about 6 mm BL and postflexion larvae are characterized by distinct medio-lateral pigmentation. Osteological development is described from a series of cleared and stained specimens. All fins have the adult complement of spines and rays by 12 mm BL. The larvae of S. emarginatum are compared with those of the European S. canthurus and other southern African sparids.     

The life-cycle and seasonal abundance of Echinoparyphium montgomeriana n. sp. (Trematoda: Echinostomatidae) in Natal,South Africa

A new species of Echinoparyphium, E. montgomeriana, is described from Durban, South Africa. Certain unusual aspects of its morphology are discussed. The adult fluke is a parasite of the alimentary tract of birds. Its larval stages are common parasites of freshwater snails belonging to the family Planor-bidae including Buiinus africanus,the intermediate host ofSchistosoma haematobium and S. mattheei in the area. These intra-molluscan stages are shown to have a seasonal transmission cycle.     

Buffalo (Bubalus bubali) Late Embryo and Foetus Development: A Morphological Analysis

Many researches describe the embryonic developmental features in domestic animals; however, in farm animals, they are scarce. Most farm animal studies are related to assisted reproduction and embryos transfer techniques. But, morphological features and size measure to estimate the age gestation are rarely reported in literature. Thus, in this study, we described the developmental changes in the bubaline (Bubalus bubali) concepts from 21 to 60 days of gestation. Our results revealed that buffalo embryos similar morphological characteristics similar to other mammalian species. Also, similarities between bovine and bubaline persist; except on foetal stages when buffalos have a faster development than bovine. Therefore, buffalo's gestation period exhibits some varieties and accurate embryo age is more difficult. Yet, when we use a combination of the crown–rump, macroscopic analysis and alizarin red, it is possible to describe better the whole embryogenesis stages of the buffalo and which can contribute for future reproduction researches and applications in veterinary practice.     

Larval Development of the Congrid EEL Gnathophis Capensis (KAUP), off Southern Africa,with Notes on the Identity of Congermuraena Australis Barnard

Nauplii and copepodid developmental stages of the estuarine copepod, Pseudodiaptomus hessei, are described and illustrated. Five post-embryonic naupliar and five copepodid stages (excluding adults) are distinguished. Diagnostic characteristics separating stages are also tabulated.     

Isolation,characterization, and in vitro differentiation of ovine amniotic stem cells

Challenge tests with Artemia four different development stages (nauplii, metanauplii, pseudoadults and adults) to white spot syndrome virus was carried out by immersion challenge and virus-phytoplankton adhesion route in order to asses the possibility of Artemia acting as a vector of WSSV to penaeid shrimp Litopenaeus vannamei postlarvae. The WSSV succeeded in infecting four stages Artemia, and nested-PCR detection for WSSV revealed positive results to virus-phytoplankton adhesion route. No mass mortalities were observed in penaeid shrimp postlarvae fed with WSSV-positive Artemia which exposed to WSSV by virus-phytoplankton adhesion route, whereas WSSV DNA detected in penaeid shrimp postlarvae by nested-PCR. By contrary, no WSSV-positive was detected in any animal fed with WSSV-negative Artemia. These results indicated that Artemia could serve as a vector in WSSV transmission.     

Developmental stages of the blue‐breasted quail (Coturnix chinensis)

Chickens and Japanese quail (Coturnix japonica) have traditionally been the primary avian models in developmental biology research. Recently, the blue‐breasted quail (Coturnix chinesis), the smallest species in the order Galliformes, has been proposed as an excellent candidate model in avian developmental studies owing to its precocious and prolific properties. However, data on the embryonic development of blue‐breasted quail are scarce. Here, we developed a normal developmental series for the blue‐breasted quail based on developmental features. The blue‐breasted quail embryos take 17 days to reach the hatching period at 37.7°C. We documented specific periods of incubation in which significant development occurred, and created a 39‐stage developmental series. The developmental series for the blue‐breasted quail was almost identical to that for chickens and Japanese quail in the earlier stages of development (stages 1–16). Our staging series is especially useful at later stages of development (stages 34–39) of blue‐breasted quail embryos as a major criterion of staging in this phase of development was the weight of embryos and the length of third toes.     

The Zoocartographic Approach to Anuran Ecology

This is the first detailed study of the post-natal development of Aethomys chrysophilus. Physical measurements were taken from 37 litters consisting of 116 young, and the behaviour of 37 young from 12 litters was observed. The physical development of the young is described and the weight and linear increases analysed. Litter size varied between one and five with an average of 3,1 young per litter for 37 litters. The minimum age of sexual maturity was approximately 82 days, and the shortest interval between litters was 26 days. Major behavioural changes were found at six, 12 and 26 days, and on this basis the post-natal development is divided into Neonatal (0-5 days). Transition (6-11 days), Infantile (12-25 days) and Juvenile (26-82 days) periods. Nipple-clinging dominated the early stages of development and the modifications of the incisors for this purpose are described. The parent-young relationship and mortality of the young are discussed. In addition, the post-natal development of A. chrysophilus is compared with that of three other South African murids, namely Aethomys namaquensis, Thallomys paedulcus and Praomys (Mastomys) natalensis.     

Prenatal development in greater mouse‐eared bat,Myotis myotis (Borkhausen, 1797) (Chiroptera, Vespertilionidae)

Order Chiroptera is the second largest mammal group after rodents. An understanding of the development of the bats, which is a very special mammal group in terms of their lifestyles, morphology and their ability to fly, is very important because most of the adult anatomical differences characterizing species occur during organogenesis. In this study, developmental stages were determined for Myotis myotis species based on external morphological characteristics from embryos obtained from wild‐caught pregnant females. The developmental stages of M. myotis were comparable with those of other bat species.     

Description and taxonomic discussion of eimerian coccidia from African and Levantine geckoes

new genera are proposed to accomodate new and previously described species of eimerian coccidia from reptiles which undergo endogenous development either in the bile epithelium — Cholo?imoria n. gen., or in the microvillous zone of the intestinal epithelium — Acroeimeria n. gen. Endogenous development is described from 3 species, all from geckoes: C. turcicus (syn. Eimeria turcicus Upton, McAllister and Freed, 1988) from Hemidactylus turcicus in Israel; C. pachydactyli n. sp. from Pachydactylus capensis in South Africa and A. lineri (syn. Eimeria linen McAllister, Upton and Freed, 1988) from H. turcicus, Israel and H. mabouia, South Africa. Biliary epithelial cells infected by Chole?imeria become hypertrophic and are displaced to the surface of the epithelial layer. Oocysts are cyllndroid to oval, lack a stieda body and sporulate in the gall bladder. The developing endogenous stages of Acroeimeria, enclosed in the microvillous border of the host cell, expand into the intestinal lumen. Oocysts are oval-spherical, lack a stieda body and sporulation is exogenous.     

Embryonic Development of Cuban Gar (Atractosteus tristoechus) Under Laboratory Conditions

The embryonic development of Cuban gar (Atractosteus tristoechus) was described under controlled laboratory conditions. During the whole embryogenesis seven periods were defined: the zygote (0–½ h), cleavage (¾–4 h), blastula (5–10 h), gastrula (12–20 h), segmentation (24–40 h), pharyngula (48–66 h) and hatching (72–96 h) periods. The stages were based on morphological features, generally readily identified by examination of the embryo with the dissecting stereomicroscope. Hatching occurred 96 ± 4 h after spawning at 28°C.     

The development of the nasal capsule of the silver carp Hypophthalmichthys molitrix (Valenciennes)

The development of the nasal capsule, including the procartilaginous as well as some mesenchymatous developmental stages, is described in the Chinese silver carp, Hypophthalmichthys molitrix (Val.). In the nasal capsule a primitive feature, namely the presence of a complete paraphysial bridge was observed. The composition and possible origin of the ethmoidal plate, nasal septum and lamina orbitonasalis in fishes are discussed.     

In vitro development of cyathostomin larvae from the third stage larvae to the fourth stage: morphologic characterization, effects of refrigeration, and species-specific patterns

A mixed population of equine cyathostomin (Nematoda, Strongyloidea) infective third stage larvae (L3) was cultured in vitro using a cell-free medium. Some L3 were cultured immediately after Baermann collection from fecal cultures, while others were kept in water at 4 °C for 7 days before initiating the in vitro cultures. Cultures were examined daily for viability. At days 2, 7, 14 and 21 larvae were collected for identification of developmental stage and morphological changes, using both light and scanning electron microscopy. Larvae were classified as early L3 (EL3), developing L3 (DL3), late L3 (LL3) and fourth stage larvae (L4) on the basis of morphological features. Viability remained high throughout the entire study period in cultures of both non-refrigerated (84.7%) and refrigerated (77.4%) larvae. However, viability of the non-refrigerated was significantly greater from 7 through 21 days of culture. Significant differences were also observed in the percentage of DL3 between the non-refrigerated and refrigerated larval cultures by day 7. The highest percentage of DL3 larvae (22.5%) was reached at the end of study in those larvae that were not previously refrigerated. The data suggests that prior refrigeration decreases viability and slows L3 development. At day 21 LL3 larvae were only a small percentage of the DL3: 6.9 and 5% in non-refrigerated and refrigerated cultures, respectively. Few of these larvae freed themselves from the L3 cuticle and moulted to L4 stage. Characteristics of individual species in vitro developmental patterns were determined by the molecular identification of individual larvae in pools of larvae randomly collected at days 0 and 21. Seven species (Coronocyclus coronatus, Cylicostephanus goldi, Cylicostephanus longibursatus, Cyathostomum catinatum, Cylicocyclus nassatus, Cylicocyclus ashworthi, Petrovinema poculatum) were identified in the day 0 pool. The greatest tendency to develop in vitro was shown by the genus Cylicostephanus with the species C. goldi and C. longibursatus that developed to the LL3-L4 stages. C. nassatus, C. ashworthi and C. coronatus did not progress in their development beyond the EL3 stage, while no apparent signs of development were registered for C. catinatum.     

Oxygen Concentration and Cysteamine Supplementation During In vitro Production of Buffalo (Bubalus bubalis) Embryos Affect mRNA Expression of BCL‐2, BCL‐XL,MCL‐1, BAX and BID

This study examined the effects of O₂ concentration (5% vs 20%) during in vitro maturation (IVM), fertilization (IVF) and culture (IVC) or supplementation of IVM and IVC media with cysteamine (50 and 100 μm , respectively; IVM, IVF and IVC carried out in 20% O₂), on blastocyst rate and relative mRNA abundance of some apoptosis‐related genes measured by real‐time qPCR in immature and in vitro‐matured buffalo oocytes and in embryos at 2‐, 4‐, 8‐ to 16‐cell, morula and blastocyst stages. The blastocyst rate was significantly higher (p < 0.05) while the percentage of TUNEL‐positive cells was significantly lower (p < 0.05) under 5% O₂ than that under 20% O₂. The mRNA expression of anti‐apoptotic genes BCL‐2 and MCL‐1 was significantly higher (p < 0.05) and that of pro‐apoptotic genes BAX and BID was lower (p < 0.05) under 5% O₂ than that under 20% O₂ concentration at many embryonic stages. Following cysteamine supplementation, the blastocyst rate and the relative mRNA abundance of BCL‐XL and MCL‐1 was significantly higher (p < 0.05) and that of BAX but not BID was lower (p < 0.05) at many stages of embryonic development, although it did not affect the percentage of TUNEL positive cells in the blastocysts significantly. The mRNA expression pattern of these genes during embryonic development was different in 5% vs 20% O₂ groups and in cysteamine supplemented vs controls. At the 8‐ to 16‐cell stage, where developmental block occurs in buffalo, the relative mRNA abundance of BCL‐2 and MCL‐1 was highest under 5% O₂ concentration and that of BAX and BID was highest (p < 0.05) under 20% O₂ concentration. These results suggest that one of the mechanisms through which beneficial effects of low O₂ concentration and cysteamine supplementation are mediated during in vitro embryo production is through an increase in the expression of anti‐apoptotic and a decrease in the expression of pro‐apoptotic genes.     

Morphological and molecular characterization of Glossidium pedatum Looss, 1899 and Orientocreadium batrachoides Tubangui, 1931 from sharptooth catfish,Clarias gariepinus (Burchell, 1822)

The superfamily Plagiorchioidea has a considerable number of genera and species with great uncertainty of their phylogenetic position. The objectives of the current study were to specifically describe the morphology and determine for the first time the phylogenetic position of Glossidium pedatum and Orientocreadium batrachoides. Examination of G. pedatum using conventional light and scanning microscopy techniques revealed undescribed features related to the digestive system, the presence of papillae-like lateral lappets, and terminal lobes covered with backwardly directed spines. Orientocreadium batrachoides revealed a pharynx that is four lobed anteriorly. Both the large (28S) and small (18S) subunits of the ribosomal genome, analysed through Bayesian inference and maximum likelihood, were used to genetically characterise these species. Phylogenies indicate that G. pedatum does not fit well into any known family within the Plagiorchioidea, as currently indicated in various systematic structures based on morphology. However, G. pedatum was closely related to Haematoloechidae according to analyses of 18S and 28S rDNA. Based on 28S rDNA, O. batrachoides formed a well-supported clade with Orientocreadium pseudobagri within the family Orientocreadiidae. In turn, Orientocreadiidae is closely related to Leptophallidae. The current study provides essential information that could be helpful to assign the family for Glossidium in future studies. Characterisation of life-cycle stages may be necessary to fully elucidate the systematic position of G. pedatum.     

Influence of E‐cadherin genetic variation in canine mammary tumour risk,clinicopathological features and prognosis

E‐cadherin is a cell adhesion molecule that participates in several cellular processes that guarantee the maintenance of structural and functional integrity of epithelial tissues. E‐cadherin plays an important role in mammary carcinogenesis, and various studies have demonstrated the effect of CDH1 genetic variation in risk, progression and biological behaviour of human breast cancer. Although there are some recognized genetic variations in canine CDH1 gene, their influence in canine mammary tumour development and progression has not been previously evaluated. In this study, we aim to assess the influence of CDH1 SNPs rs850805755, rs852280880 and rs852639930 in the risk, clinicopathological features and clinical outcome of canine mammary tumours. A case‐control study was conducted involving 206 bitches with mammary tumours and 161 bitches free of mammary neoplasia. CDH1 SNPs rs850805755 and rs852280880 were associated with a decreased risk and a later onset of mammary tumour development. Furthermore, these SNPs were related to the development of small size carcinomas, of low histological grade and low nuclear pleomorphism. SNP rs852639930 was associated with the development of small size tumours with a non‐infiltrative, non‐invasive growth pattern. Data from the present investigation demonstrate that these CDH1 genetic variants could have a protective role in canine mammary tumours, by being associated with low risk of tumour development, delayed onset of the disease and less aggressive clinicopathological features.