Morphological and histochemical studies on the ovarian development and oogenesis in Paramphistomum cervi (Digenea: Paramphistomatidae)

The ovary in 4-week-old worms contains undifferentiated germ cells. The oogonial differentiation, together with the appearance of some PAS-positive material in the ooplasm occurs in the ovary of 8-week-old worms. The ovary of 16-week-old worms contains only oogonia and oocytes and no germ cells. In adult worms, the oocytes reach the pachytene stage and further development is arrested at this stage. Nucleolar fragmentation and subsequent transport of nuclei to the ooplasm have been observed. The ooplasm contains nutritive material rich in proteins, carbohydrates and lipids. Its amount varies with different stages of oogenesis. The localization of various phosphatases and dehydrogenases was studied during oogenesis and their functional significance was discussed.     

Effect of thiourea on the histopathology and the reproductive performance of the male flesh fly Sarcophaga ruficornis (Fabr.)

When newly emerged and 24-hour-old male flesh flies Sarcophaga ruficornis (Fabr.) were fed on food containing 1.5% thiourea for 24 h, there was a small decrease in the size of the testes in both cases. Disturbance in spermatogenesis and histopathological damage were also observed in both cases. However, in the newly emerged flies the effect was mainly on secondary spermatocytes and spermatids, while in the others the effect was more pronounced on spermatogonia. The reproductive performance in respect of the production of larvae was considerably diminished in the newly emerged treated flies and was even further diminished in flies that were 24 h old when treated. The rate of adult emergence, however, remained unaffected for both kinds.     

Ultrastructure of the male reproductive system of the trematode Brachylaimus aequans

The transmission electron microscopic studies of the trematode Brachylaimus aequans revealed that the seminal vesicle and ejaculatory duct are lined with syncytial epithelium with numerous lamellate processes. The cirrus and genital pore are covered with a spineless tegument, which is almost identical with the body tegument. The testes contain tailed spermatozoa developing during spermiogenesis from biflagellate spermatids whose flagella (9 + 1) fuse with the median cytoplasmic process. The lumina of seminal vesicle, ejaculatory duct and cirrus are filled with spermatozoa.     

A study of proteases throughout the life cycle of Trichinella spiralis

In the present report we study the proteolytic activity of the excretion-secretion and crude extracts of different stages of Trichinella spiralis (Owen, 1835) Railliet, 1895, (muscle-stage larvae, adult worms before and after mating, and newborn larvae) using natural substrates (structural and hematic mammalian proteins). The analysis of the results allow us to set up a certain stage-specificity, as well as an important relationship between the protease patterns throughout the parasite life cycle and how the parasite may overcome both mechanical and humoral barriers within the host. Muscle-stage larvae present a great activity against structural proteins (collagen), while newborn larvae and adult worms degrade principally hematic proteins (hemoglobin, fibrinogen and immunoglobulin G).     

Effects of dieldrin and sumithion on the amino acid nitrogen and proteins in the haemolymph of desert locust Schistocerca gregaria Forsk

The changes in amino acid nitrogen, proline, and proteins in the haemolymph of desert locusts at different stages of dieldrin and sumithion posioning are reported using techniques of colorimetry, polyacrylamide gel electrophoresis, Sephadex gel chromatography, and electro-gel chromatography.Both the insecticides did not alter amino acid nitrogen and proline titers during the initial stages of poisoning. However, drastic changes were noted at the later stages. In comparison to amino acid nitrogen, the depletion in proline content was of much higher magnitude. Initially the protein content of haemolymph depleted and increased significantly at the acute poisoning stage. Several changes in the electrophoregrams and protein elution profiles were noted in the haemolymph samples of treated insects. Many new proteins were detected in treated insects and their molecular weights, diffusion coefficients, and Stoke's radii are reported.These results are discussed in relation to current ideas of protein metabolism in insects. Further, a possible role of haemolymph proteins as insecticide carriers has been postulated.     

Toxico-pathological effects of cypermethrin upon male reproductive system in rabbits

The objective of this work was to identify the reproductive toxico-pathological effects of cypermethrin (CY) in mature male rabbits. Apparently healthy adult age- and weight-matched rabbits (n = 40) were procured from the local market, kept under similar management conditions and divided into four equal groups. Different doses of CY (50, 100 and 150 mg kg⁻¹ body mass) mixed in mustard oil were injected intraperitonealy at weekly intervals in male rabbits (groups B-D) prior to mating. Group A served as control and each animal in this group received equivalent volume of mustard oil. Treatment was continued for 71 days. Decreased testicular and epididymal sperm counts were recorded mostly in dose and time dependent manner in CY-treated rabbits. The serum testosterone concentrations in CY-treated rabbits were significantly lower than those of control group. Degeneration, arrested spermatogenesis and connective tissue (CT) proliferation in testes, while sperm-less seminal plasma and tailless spermatozoa in epididymis of CY-treated rabbits were observed. It was inferred that CY-induced defects in sperms and pathological alterations in testes and epididymis.     

Transient expression of gfp in the obligate biotrophic oomycete Plasmopara halstedii using electroporation and a mechanoperforation method

Studying plant biotrophic oomycetes is difficult, because they depend on living plant cells for nutrition, which necessitates investigations in planta . Internal optical labelling is a powerful tool for analysing intra- and interspecific interactions. Different approaches are described for establishing a gfp -transformation system for Plasmopara halstedii , the causal agent of sunflower downy mildew. A vector containing gfp and the oomycete-specific ham34 regulators from Bremia lactucae was constructed for transformation experiments. Particle bombardment of infected sunflower cotyledons during different developmental stages of the pathogen did not result in successful transformation. In contrast, transient gfp expression in sporangia was achieved using electroporation. However, gfp expression was lost during the subsequent round of infection. A novel transformation method for biotrophic organisms in planta employing mechanoperforation – so-called Löchern–resulted in sporangiophores of P. halstedii transiently expressing gfp and emerging distant from the site of transformation. The new technique is advantageous compared with others as the transformed hyphae can recover during their vegetative growth, before reproductive structures occur. This first step lays an important foundation for further investigations of obligate biotrophic organisms.     

Taxonomic status of Ascocotyle (Phagicola) rara Arruda, Muniz-Pereira et Pinto, 2002 (Digenea: Heterophyidae)

Holotype and paratype of Ascocotyle (Phagicola) rara Arruda, Muniz-Pereira et Pinto, 2002, a heterophyid trematode recently described on the basis of two worms collected by Lauro Travassos in 1921 in the intestine of Ixobrychus exilis (Gmelin) from Brazil, were studied. The morphology of the worms revealed their conspecificity with Ascocotyle (Phagicola) angeloi Travassos, 1928 found in the same host. Both the taxa have a similar length (between 600 and 900 microm) and shape of the body (long pyriform), the long intestinal caeca reaching to the ovarian level, a long posterior muscular prolongation of the oral sucker and the prepharynx, transverse uterine loops situated between the ventral sucker and testes, and the gonotyl with more than 20 digitiform pockets. Consequently, A. (P.) rara is proposed as a junior synonym of Ascocotyle (Phagicola) angeloi.     

Ecdysial failures in the cotton boll weevil: Synergism of diflubenzuron with juvenile hormone

The frequency and etiology of ecdysial failures occurring during the pupal-adult transformation of the cotton boll weevil, Anthonomus grandis, was studied after treatment with juvenile hormone (JH) and/or diflubenzuron (DFB). Failure at emergence was the result of inability of the adult insects to escape from their pupal exuviae. Teratogenic effects in the form of pupal-adult intermediates or adults with pupal characters were not obtained with JH or DFB treatment after the larval-pupal ecdysis. Combining JH with the DFB treatment yielded a synergistic response that increased the frequency of ecdysial failures about sevenfold when applied in the later pupal stages. The fine structure of the abdominal cuticle of adults experiencing ecdysial failure after treatment with JH as white-eyed pupae exhibited granular deposits within the lamellar region and interference with deposition of the nonlamellate endocuticle. DFB treatment of the earlier pupal stages interfered with deposition of the lamellate cuticle by eliminating or reducing the lamellar structure. It was concluded that the primary interaction of JH with DFB was that of extending or reinitiating DFB sensitivity in the later pharate adult. A secondary interaction may involve inhibition of cuticle hardening as both JH and DFB appear to inhibit the tanning process of adults treated as white-eyed pupae.     

Impact of chlorfenvinphos, an organophosphate insecticide on human blood mononuclear cells (in vitro)

In the present study, the investigation of the effect of chlorfenvinphos (CFVF) on necrotic and apoptotic changes as well as on selected morphological and biochemical parameters in human blood mononuclear cells were investigated.We analyzed the effect of this compound on proteins damage and free-radical formation in human blood mononuclear cells. Furthermore, changes in the size (FSC-A) and granularity (SSC-A) of human blood mononuclear cells exposed to chlorfenvinphos were assessed. In order to detect apoptosis, two testes were used including analysis of YO-PRO-1 iodide/propidium iodide and Annexin V/propidium iodide staining, which revealed that chlorfenvinphos increased the number of apoptotic cells at its highest concentration of 250 μM. Chlorfenvinphos at the concentrations from 50 and 100 μM increased the size and granularity of the blood mononuclear cells, respectively. Moreover, chlorfenvinphos induced the statistically significant loss of human blood mononuclear cells viability at the concentration of 250 μM. Protein damage (the increase in carbonyl groups content) was provoked by CFVF at concentrations of 100 μM and 250 μM. Furthermore, chlorfenvinphos from relatively low concentrations of 5 μM induced reactive oxygen species formation (ROS).Conclusion: The present findings provide information that chlorfenvinphos only at 250 μM is harmful to human blood mononuclear cells, the concentration which may appear in the organism only as a result of acute or subacute poisoning. Lower concentration (5-50 μM), which caused changes in level of ROS formation can affect human organism as a result of environmental exposure.     

Protective effects of garlic (Allium sativum) extract upon lindane-induced oxidative stress and related damages in testes and brain of male rats

The purpose of this study, carried out on male Wistar rats, was to evaluate the beneficial effects of garlic (Allium sativum) extract injections upon lindane-induced damages in testes, brain and thyroid function. Under our experimental conditions, lindane poisoning (in drinking water for 30 days, supplying about 50 mg/kg body weight per day) resulted in a decreased weight of testes, epididymides, prostate gland and seminal vesicles (−52%, −42%, −50% and −5%, respectively), a decrease of spermatozoa count and motility (−56%, −37%, respectively), an increased level of free thyroxin (+84%) and decreased levels of TSH and FSH in serum (−74%, −77%, respectively). In addition, lindane treatment triggered an oxidative stress in testes and brain as revealed by an increased level of lipids peroxidation (TBARS) (+96%,+92%), an increase of superoxide-dismutase activity in testes (+69%) and a decrease of glutathione-peroxidase and catalase activities in testes and brain (−52%, −34% and −49%, −45%, respectively). These lindane-induced changes were almost reversed to normal in animals injected with a garlic extract (an amount corresponding to 300 mg fresh garlic/kg/day), what confirms a beneficial effect of this vegetal source of anti-oxidants.     

Modelling the effects of wetness duration and fruit maturity on infection of apple fruits of Cox's Orange Pippin and two clones of Gala by Venturia inaequalis

The effects were investigated of fruit maturity and duration of wetness on infection of apple fruits by Venturia inaequalis , and subsequent scab development. Incubation rate (inverse of median incubation period) increased linearly with increasing temperature (5–20°C) on detached 5-week-old fruits of cv. Royal Gala. Fruits were highly susceptible in the early stages of development, but became increasingly resistant as they matured. Inoculation of attached 12-week-old and detached near-mature fruits did not result in any lesions, while inoculation of attached 4-, 5-, 7- and 9-week-old fruits resulted in various levels of infection. Fruits of cv. Mondial Gala were more susceptible than those of cv. Cox's Orange Pippin. On cv. Mondial Gala, a wet period of 9 h resulted in ≈ 90% infection of 4-week-old fruits, but only 9% infection of 9-week-old fruits. Numbers of scab lesions on an apple generally followed a Neyman type A rather than a Poisson distribution, indicating a certain degree of aggregation of lesions on a fruit. A two-parameter generalization of the Poisson model described the observed incidence–density relationship well. A longer duration of wetness was required to result in a similar level of scab infection on old fruits to that on young fruits. On cv. Mondial Gala, wet periods of 9 and 32 h were required for ≈ 90% incidence of fruit scab on 4- and 7-week-old fruits, respectively. A mathematical model was developed to relate the incidence of fruit scab to duration of wetness and fruit maturity. The potential use of these results in practical disease management is discussed.     

Histochemistry of the cercaria of Orientobilharzia turkestanica (Skrjabin, 1913)

Four types of gland cells--escape, head, praeacetabular and postacetabular--were demonstrated by histochemical methods in the cercaria of Orientobilharzia turkestanica. The secretion of the head gland contains proteins with cystine and phospholipids. It exhibits the acid phosphatase activity. The secretion of the escape glands contains proteins with cystine and cysteine and the secretion of the postacetabular gland cells proteins with cystine, cysteine and tyrosine, and neutral and acid mucosubstances.     

Laboratory studies on the influence of the earthworm Eukerria saltensis (Beddard) (Oligochaeta: Ocnerodrilidae) on overlying water quality and rice plant establishment

Dense infestations of a peregrine oligochaete worm, Eukerria saltensis (Beddard), have been linked to rice crop failures in southern New South Wales, Australia. The influence of E. saltensis on water quality and rice plant establishment was investigated in a series of laboratory experiments using a flooded Riverina clay soil. Worm densities of 20 and 40 per container (2548 and 5096 worms/m², respectively) significantly increased water turbidity after 7 days incubation. Longer incubation periods led to turbidity levels of over 500 NTU being achieved (40 worms per container, 21 days incubation). Water pH was significantly reduced by densities of 10, 20, and 40 worms per container after 7 days under cyclical illumination, however in continuous darkness significant changes in pH related to worm density were only found after 21 days incubation. Nitrogen as NH₄+ and total phosphorus increased significantly in the overlying water in response to increasing worm densities after 21 days incubation, however nitrogen as nitrate/nitrite and soluble phosphorus did not. Algal production (measured as extracted chlorophyll a concentration) was unaffected by the worms, reflecting the low concentrations of available phosphorus in all treatments. Rice plants grown in containers with worms produced significantly longer and heavier shoots than control plants. Root systems were unaffected, and there was no evidence of root abrasion. Evaluation of rice seed stratification in the soil profile indicates that rice seeds can be passively transported below the soil surface by the feeding and tunnelling activity of E. saltensis. Our results suggest that E. saltensis impedes the establishment of aerially-sown rice crops primarily by increasing water turbidity. Plants respond to high turbidity by partitioning more of their growth into shoot production, and consequently become vulnerable touprooting through wave action, particularly as the soil loses compaction because of worm activity. Maintaining the lowest possible water levels during rice crop establishment has helped farmers to minimize these effects.     

Some aspects of histochemical studies on the parasite and tissue reaction in bovine cysticercosis

Histochemical studies on the cysticercus and surrounding tissue reaction were performed at various intervals after experimental infection. It was found that acid mucosubstances and proteins with SH- and SS-groups appeared first in the granulation tissue around the cysticercus (on about day 14 p.i.) and only later (on day 28 p.i.) in the tegument of the cysticercus where they were localized in the rim of microtriches. This envelope consisting of mucosubstances and proteins seems to be identical with the electron-dense substance found on the surface of developing cysticercus during electron-microscopical studies. It is considered to be a mimicry enabling the cysticerci to survive even in an immunologically unfavourable environment. Phospholipids were found in activated fibroblasts and in some cells of macrophage type on days 21 and 30 p.i. and in a large number in subtegumental cells of cysticercus on days 28-34 p.i. This phenomenon seems to be correlated with the increased activity of subtegumental cells of the larva in this period. In morphologically fully differentiated cysticerci, the reaction for phospholipids in subtegumental cells and distal cytoplasm was only feebly positive. Phospholipids were not detected in the rim of microtriches at any time after infection.     

Histochemistry of the racemose form of Cysticercus cellulosae.

The racemose form of brain cysticercosis arises from an intense proliferation of the bladder wall after the scolex part has degenerated. The proliferating zones are 2-3 times thicker than the remaining parts of the bladder and are characterized by a densely folded tegument and thick subtegumental and parenchymal layers. The tegument and subtegumental cells contain a large amount of acid mucosubstances with sulpho groups and hydrophilic lipids, and exhibit a high activity of alkaline and acid phosphatases. The parenchyma contains a large amount of glycogen. With the gradual aging of the bladder wall and with the first signs of autolysis, the enzymatic activity as well as the amounts of glycogen, neutral and acid mucosubstances, and proteins decrease, and the hydrophobic lipids prevail over the hydrophilic ones. The results obtained are important for the differential diagnostics of cestode larval stages in the human brain.     

The ecology of Crepidostomum species (Allocreadiidae: Digenea) in the salmonoids of Lake Yli-Kitka in northeastern Finland

Crepidostomum spp. were studied from 417 whitefish (Coregonus acronius Rapp, 1854), 220 vendace (Coregonus albula L.) and 38 brown trout (Salmo trutta m. lacustris (L.)) from Lake Yli-Kitka in northeastern Finland during 1980-1983.12.7% of the whitefish were infected with Crepidostomum with a mean intensity of 4.6 worms per infected fish. The species involvedare C. farionis (Müller, 1784) and Crepidostomum wikgreni Gibson et Valtonen, 1988, which differed from C. farionis in the number and size of the eggs. Both types were encountered in the gall-bladder and intestine, but were unable to be distinguished as immature stages. 21% of the brown trout harboured C. farionis in the intestine with a mean number of 1.5 worms per infected fish. Two C. farionis specimens occurred also in the intestine of one vendace. Whitefish smaller than 150 mm did not harbour Crepidostomum specimens, but in bigger fish the prevalence and the mean intensity of infection increased to a certain limit as the fish got larger. The prevalence of Crepidostomum infection also clearly increased during the three seasons in the three size-groups studied. The seasonal pattern of Crepidostomum in whitefish of the size greater than or equal to 150 mm was variable in that the lowest values, both in the prevalence and mean intensity of infection, occurred between September and December in 1980 and between April and August in 1982. Reinvasion was found throughout the year, although the main recruitment occurred during autumn and early winter. Eggs matured between late spring and early autumn. The smallest worms occurred mainly in the gall-bladder, and most of the gravid specimens were located in the intestine. Both the variance-to-mean ratio and the low values of the parameter k of the fitted negative binomial distribution reveal the Crepidostomum specimens are overdispersed in the whitefish of Lake Yli-Kitka.     

交配次数对云斑天牛雌虫精子消耗量及产卵量的影响

通过室内饲养观察和解剖云斑天牛雌虫生殖系统,研究了单次和多次交配对云斑天牛雌虫精子数量的消耗、产卵量、产卵历期和寿命的影响,并对云斑天牛雌虫生殖系统、精子形态及精子在雌虫生殖系统中的分布动态进行了研究。结果表明,多次交配的云斑天牛雌虫交配-受精腔内的精子数量长期保持在80万个左右,而单次交配的云斑天牛雌虫交配-受精腔内精子数量随着天数的增加而下降。多次交配的雌虫产卵量(31.44粒)和产卵历期(30.12d)都显著大于单次交配雌虫的产卵量(27.88粒)和产卵历期(25.75d)(P<0.05);多次交配的雌虫寿命低于单次交配的雌虫,但两者差异不显著(P>0.05)。     

Teratogenic effects of the fungicide benomyl on posterior segmental regeneration in the earthworm,Eisenia fetida

Earthworms, Eisenia fetida, were treated by surface exposure to the fungicide benomyl at various stages of posterior segmental regeneration. Teratogenic effects of benomyl were observed when worms were treated 7–11 days after amputation (i.e. during the normal period of segmental replication), but not during days 1–5, 13–17, or 19–23. Teratogenic effects included a reduction in the number of regenerated segments, an increased frequency of segmental groove anomalies, and a variety of monstrosities. The effects of benomyl treatment on the number of regenerated segments and frequency of anomalies were dose-dependent within a narrow concentration range (approximately 0.2–5.0 mg litre^?1); at higher concentrations (e.g. 25 mg litre^?1) teratogenic effects were less frequent because the onset of segmental delineation was delayed until well after exposure. Non-invasive electrophysiological recordings from treated worms indicated that functional integrity of giant nerve fibre conduction pathways was established in all anomalously regenerated tail segments, except in a two-tailed monstrosity. The evidence supports the hypothesis that these teratogenic effects derive from an antimitotic mode of action of benomyl on segmental regeneration.     

Histochemistry of gland cells of Eurytrema pancreaticum cercariae.

The cercariae of Eurytrema pancreaticum (Janson, 1889) possess four types of gland cells - proper cystogenic, penetration, ventral and dorsal gland cells. The secretion of ventral and dorsal gland cells is released into the tegument. The proper cystogenic gland cells are the largest and their contents serve for the formation of the cyst wall of metacercariae in the second intermediate host. The secretion of proper cystogenic gland cells contains besides neutral mucosubstances also acid mucosubstances with both carboxyl- and sulphogroups digestible with beta-glucuronidase. The secretion of penetration gland cells contains neutral mucosubstances and proteins with tyrosine, tryptophan and SS groups. The ventral gland cells contain mostly acid mucosubstances with sulphogroups, which are digested with beta-glucuronidase, and proteins with tyrosine, tryptophan and SH groups. The rudimentary dorsal gland cells contain a small amount of acid mucosubstances. The whole tegument of cercariae and the two main collecting canals of the excretory system exhibit a high alkaline phosphatase activity. The nerve ring and the main nerve truncs contain proteins with SH groups and hydrophilic lipids and exhibit a cholinesterase activity. The suckers contain a larger amount of glycogen.