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.     

Some specific and non-specific phosphatases of the sporocyst of Fasciola hepatica. II. Enzymes associated with the membrane transport

Using histochemical and cytophotometric methods, enzymes responsible for the membrane transport (alkaline phosphatase, adenosine triphosphatase, and 5-nucleotidase) in the developing sporocyst of Fasciola hepatica (L., 1758) were studied. The most active metabolism occurred in the germ balls of sporocysts on the 8th and 15th days of development, which is associated with intensive proliferation and subsequently differentiation of embryos within the germ balls.     

Morphology, histochemistry and ultrahistochemistry of special verrucose formations in daughter sporocyst of Eurytrema pancreaticum

Verrucose formations were found on the surface of fully developed sporocysts of E. pancreaticum Janson, 1889 at the site where the attenuated proboscis-like anterior portion widens into the posterior portion. Under these verrucose formations is always a group of gland cells. Their narrowed processes pass at a common site through the muscle layer and above this layer again slightly widen and project above the neighbouring tegument. The tegument of the verrucose formation differs from the neighbouring tegument of the sporocyst. In the cytoplasm of the gland cells there are large, spherical membrane-bound bodies containing proteins with tryptophan, tyrosine and SH groups. These bodies do not have any activity of alkaline phosphatase, acid phosphatase or nonspecific esterase. Besides these protein bodies the perinuclear cytoplasm is filled with beta glycogen particles and many cisternae of endoplasmic reticulum. The processes of these cells contain thick fibriles. The verrucose formations with the gland cells seem to serve for attachement and lysis. This function is applied not only during the development of the sporocyst, but also during its release from the site of location and penetration through the snail tissue.     

Ultrastructural observations on the redia of Echinostoma revolutum (Froelich, 1802)

E. revolutum redia digestive and excretory system ultrastructure, as well as body wall tegument were studied in TEM. The body tegument protrudes in short microvilli and contains uni- and multiciliate sensory endings. The anterior part of the digestive system (pharynx, short oesophagus) is lined with body tegument, the caecum being covered with a flat epithelium with sporadic microvilli. Oesophageal gland cells are filled with minute electron-dense granules. The excretory capillaries joined to large flame cells are composed of spirally wrapped cells, in the cytoplasm of which there are clusters of microtubules. The special features of the digestive system of echinostome rediae, as well as their significance in the antagonistic relationship to the partenitae of other families of trematodes and their pathogenic effect on the intermediate host, are discussed.     

小地老虎化学感受蛋白AipsCSP2配体结合特性分析

为了明确小地老虎化学感受蛋白基因AipsCSP2在雌、雄成虫各组织中的表达情况,解析AipsCSP2蛋白的配体结合特性并探讨其功能.本文基于小地老虎性腺转录组数据,利用PCR技术克隆AipsCSP2基因,并进行生物信息学和系统进化分析;采用qPCR技术测定该基因在小地老虎雌、雄成虫不同组织中的表达水平;利用原核表达技术...     

Chaetotaxy of the monogeneans Macrogyrodactylus clarii and m. congolensis from the gills and skin of the catfish clarias gariepinus in Egypt, with a note on argentophilic elements in the nervous system.

A comparison has been made between the chaetotaxy of the gyrodactylid monogeneans Macrogyrodactylus clarii Gussev, 1961 and M. congolensis (Prudhoe, 1957) Yamaguti, 1963 from the gills and skin, respectively, of the catfish Clarias gariepinus (Burchell) from the river Nile in Egypt. Bilaterally arranged argentophilic structures on the surface of these parasites are presumed to be sensilla and are more abundant in M. clarii than in M. congolensis especially on the ventral surface (124 vs. 66). In both species these sensilla are concentrated on the head lobes and in the pharyngeal region, but there are features of the sensilla patterns that can be used to distinguish the two species. Comparison is made with sensilla patterns of other gyrodactylids. A system of cells and dendritic processes, most probably part of the nervous system, also has an affinity for silver in the two species. There are no previous records of extensive argentophilic elements in the nervous systems of monogeneans.     

Influence of pesticides on the activity and kinetics of invertase,urease and acid phosphatase enzymes

The effects of four pesticides (three herbicides, atrazine, paraquat, glyphosate, and an insecticide, carbaryl) on the activity and kinetics of an invertase (from yeast), a urease (from jack bean) and an acid phosphatase (from potato) were investigated. Glyphosate and paraquat showed a marked activation effect on invertase activity. From the dependence of V_max and K_m parameters on pesticide concentrations, a mixed-type activation mechanism was suggested. The kinetic behaviour of urease and acid phosphatase appeared to be uninfluenced by both pesticides. Methanol, used as solvent for both carbaryl and atrazine, inhibited invertase, urease and acid phosphatase with, respectively, competitive, non-competitive and uncompetitive mechanisms. The extent of the inhibition was different, as estimated by the values of the inhibition constant K₁. An additional inhibition effect of urease and invertase activities was achieved in the presence of carbaryl, whereas no influence was detected on the activity and kinetics of acid phosphatase. Finally, atrazine was shown to alter the kinetics of the enzymes only at higher concentrations.     

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.     

水盐胁迫对干旱区植物根际土壤酶活性的影响

为了对比自然状态下水盐胁迫对艾比湖湿地自然保护区植物根际土壤酶活性的影响,采用抖落法,对艾比湖东南区域不同群落内根际土壤酶活性进行了研究,发现:随着土壤含水量的增加,根际土壤酶的活性增加而非根际土壤酶活性受到抑制;不论是根际或非根际土壤,高盐分含量限制过氧化氢酶和脲酶的活性,增加中性磷酸酶和碱性磷酸酶的活性;土壤酶活性与土壤有机质显著正相关,且大都呈现出碱性激活的特点;植物的存在降低了环境的胁迫,极大改善了根际土壤的微环境。不同样地及不同土壤剖面层中土壤酶活性的限制因子不同,分析酶活性限制因子时要区别对待、综合考虑。     

Infection of Rice Plants with the Sheath Blight Fungus Causes an Activation of Pentose Phosphate and Glycolytic Pathways

The response of key regulatory enzymes of the pentose phosphate and glycolytic pathways in disease development was assessed in genetically-related rice plants resistant and susceptible to the sheath blight fungus, Rhizoctonia solani. The plants were grown and maintained under greenhouse conditions and inoculated at 50% flowering. Uninoculated healthy plants served as controls. The activities of pentose phosphate pathway enzymes (glucose-6 phosphate dehydrogenase and 6-phosphogluconate dehydrogenase) increased more than two-fold in both the resistant and susceptible plants. Activities of ATP- and pyrophosphate-dependent phosphofructokinase and phosphoenolpyruvate phosphatase increased in infected plants while activity of phosphoenolpyruvate carboxylase in infected plants was lower than in the healthy plants. Furthermore, for enzymes with increased activity, the levels were higher in the resistant line than in the susceptible line. The enhancement of the enzyme activities correlated well with the post infection period. These data suggest that altered carbohydrate metabolism in sheath blight infections may play an important role in modulating the rice plant's response to infection. The isolation of an infection-induced gene encoding a basic enzyme of pentose phosphate and glycolytic pathways could be used to develop plants with more resistance towards sheath blight disease.     

Influence of glyphosate on selected plant processes

Biochemical effects of glyphosate have been examined with a variety of plant materials using mostly merislematic or actively growing tissues. The accumulation of chlorophyll was severely retarded and photosynthetic CO₂ uptake was inhibited to a lesser extent. These inhibitory effects could not be alleviated by the simultaneous admixture of divalent cations. Glyphosate enhanced the initial substrate-induction of nitrate reductase, but repressed induction of nitrite reductase, in Ihe latter case correlating with both inhibition of chlorophyll accumulation and CO₂ uptake. Inhibition of macromolecule synthesis in single node buds of Agropyron repens(L.) Beauv. was due partly to inhibition of ¹⁴C-precursor uptake. The specific activity of soluble acid phosphatase was enhanced as was the evolution of ethane. Ethylene production was not greatly affected. A marked decrease in microsomal protein was observed but the specific activities of several microsomal enzymes did not decline. Glyphosate had little inhibitory effect on the activity of microsomal ATPases in vitro.     

Induction of branchial enzymes in snake head (Channa striatus) by oxydemeton-methyl

The effects of acute and chronic exposures to a sublethal concentration (1.7 mg/liter) of oxydemeton-methyl (Metasystox) on the activities of branchial enzymes Na, K-ATPase, Mg-ATPase, alkaline phosphatase, acid phosphatase, aspartate aminotransferase, and alanine aminotransferase were determined. While chronic and acute treatments inhibited Na, K-ATPase and Mg-ATPase concentrations, an insignificant rise in the activities of alkaline and acid phosphatases was noticed in the acute treatment. However, both chronic exposures decreased the activities of these phosphatases. A progressive accumulation of AAT and AlAT, with a maximum occurring after 30 days, was recorded. The significance of the results are discussed.     

毛缺沟姬蜂雌性内生殖器官的结构及其发育

报道了毛缺沟姬蜂Lissonota setosa(Geoffroy)成虫雌性内生殖器官的结构及其发育的系统观察结果。雌性成虫内生殖器官包括一对卵巢、两条侧输卵管、一条中输卵管、一个受精囊和一个附腺。成虫期卵巢生长速度随日龄是先加快后变慢。成虫期内其它生殖器官一般随日龄的增长而增大,达到一定程度后基本保持稳定。     

Some aspects of the biology and life history of Bothitrema bothi (Monogenea: Bothitrematidae) from the flounder Scophthalmus aquosus (Bothidae) from New Jersey, USA

Bothitrema bothi (MacCallum, 1913), a monopisthocotylean monogenean (Bothitrematidae) found on gills and occasionally on the olfactory rosette within the nares of the bothid flounder, Scophthalmus aquosus (Mitchill, 1815), is distributed along the Atlantic coast of the USA from Woods Hole, Massachusetts to Delaware Bay. This study details aspects of the morphology, microecology and biology of the oncomiracidium, juvenile and adult. Adult worms occur almost exclusively between rakers on the first and second gill arches while juveniles occupy secondary gill filaments. Analysis of variance revealed significant arch, side and position effects. Worm attachment and position is maintained largely by suction generated by a circular seal using its 54 radially arranged accessory haptoral sclerotised elements and a marginal valve. A small anterior appendix with two marginal hooks lies dorsal to a deep anteromedian cleft in the haptor, which, together with wall muscles, creates and releases the negative pressure required for attachment. Four pairs of gland openings in the ventrolateral margins of the anterior adhesive area produce secretions for attachment. Operculate eggs with four rounded protuberances and a filament are laid individually at four-minute intervals at 22 degrees C. Hatching occurs in five days at 20 degrees C. Oncomiracidia have two pairs of eyes, with the posterior pair fused, show both positive and negative phototaxis and swim at a mean rate of 5.2 mm/s at 22 degrees C. Larvae have a circle of 16 hooks and a pair of hamulus primordia. Other accessory haptoral sclerotised structures arise de novo in juveniles after attachment to the host. These data will help to resolve more clearly the relationships of the Bothitrematidae within the Monopisthocotylea.     

Toxic effects of novel organophosphorus insecticide (RPR-V) on certain biochemical parameters of euryhaline fish, Oreochromis mossambicus

The euryhaline fish, Oreochromis mossambicus was exposed to sub-lethal concentration (0.017 mg L⁻¹) of a novel phosphorothionate, 2-butenoic acid-3-(diethoxy phosphinothionyl) ethyl ester (RPR-V) for 30 days and allowed to recover for 7 days. Important biomarker enzymes were assayed in plasma, brain, gill, liver, kidney, and muscle during exposure tenures of day-3, -7, -15, -30, and also at 7 days (withdrawal) after stopping treatment. Acetylcholinesterase (AChE) activities of brain, gill, and muscle were strongly inhibited by 67, 75, and 66%, respectively, on day-30. Exposure (time) dependent increases in alanine aminotransferase (ALAT), and aspartate aminotransferase (ASAT), acid phosphatase (AcP), and alkaline phosphatase (AkP), activities in plasma and kidney; AcP and AkP activities in gill were noticed. However, significant decrease in ALAT, ASAT, AcP, and AkP activities in liver was observed. The depletion of glycogen was observed in liver, brain, and gill tissues, an indication of typical stress related response of the fish with pesticide. A significant increase in lactate dehydrogenase (LDH) activity in gill and brain was observed and decreased in liver and muscle, indicating tissue damage and muscular harm. Depletion of glutathione (GSH) was observed in the above tissues, there by enhancing the lipid peroxidation resulting in cell damage. The induction in hepatic glutathione-S-transferase (GST) levels indicates the protection against the toxicity of xenobiotic-induced lipid peroxidation. There was a significant recovery in all the above biochemical parameters, in all the tissues of fish after a recovery period of 7 days. These results revealed that RPR-V affects the intermediary metabolism of O. mossambicus and the increase of biomarker enzymes in plasma, might be due to the necrosis of liver.     

Secreted phosphatase activities in trypanosomatid parasites of plants modulated by platelet-activating factor

ABSTRACT The secreted phosphatase activities of two trypanosomatid parasites were characterized and compared with supernatants of living cells. The plant parasite Phytomonas fran?ai and the phytophagous hemipteran parasite Herpetomonas sp. hydrolyzed p-nitrophenylphosphate at a rate of 15.54 and 6.51 nmol Pi/mg of protein per min, respectively. Sodium orthovanadate (N(a)VO(3)) and sodium fluoride (NaF) decreased the phosphatase activities. The phosphatase activity of P. fran?ai was drastically diminished (73% inhibition) in the presence of sodium tartrate, whereas the phosphatase activity of Herpetomonas sp. was inhibited by 23%. Cytochemical analysis showed the localization of these enzymes on the external surface and in the flagellar pocket of the two trypanosomatids. Sodium tartrate inhibited this reaction, confirming the biochemical data. Platelet-activating factor modulated the phosphatase activities, inhibiting P. fran?ai activity and stimulating Herpetomonas sp. phosphatase activity.     

Development and physiology of infection by the downy mildew fungus Peronospora parasitica (Pers. ex Fr.) Fr. in susceptible and resistant Brassica species

The growth of two isolates of the downy mildew fungus Peronospora parasitica , one obtained from cauliflower ( Brassica oleracea ) and the other from oilseed rape ( B. napus ) was assessed in their respective hosts of origin, and also in the alternative combination. Both isolates were capable of infecting either host, but there were marked contrasts in the time course and extent of mycelial development, the amounts of associated host-cell necrosis, and eventual intensity of sporulation. Oilseed rape, which was partially resistant to the isolate from cauliflower, exhibited extensive necrosis of mesophyll cells, in conjunction with reduced mycelial development, and delayed and reduced sporulation by the pathogen. The isolate from oilseed rape was virulent on both host species. Pathogenesis in the susceptible combinations was accompanied by large increases in electrolyte leakage, and increased activity of the enzymes β-glucosidase, ribonuclease, and peroxidase. Effects on chlorophyll content were variable and activities of acid phosphatase and acid phosphodiesterase were unaffected. Electrophoretic analyses of extracts from fungal sporangia and infected seedlings indicated that the large increases in β-glucosidase were of pathogen origin, while evidence from inhibitor studies suggested that enhanced ribonuclease activity was due to a new post-infectional form of the enzyme. The significance of these findings is discussed in relation to pathogenesis and host resistance mechanisms.     

Microscopical anatomy of larva of Cheladonta costulata (Acarina: Trombiculidae). I. Glands

The larva of Ch. costulata possesses seven paired glands which can be differentiated according to their position and histological structure. In five of them, the dynamics of their secretory or excretory activity may be studied histologically during the feeding process, when not only the deposition of secretion in the gland cells, but also the size of the whole gland is changed. The morphology of the remaining glands is not affected by feeding.     

水稻品种抗性对白背稻虱羧酸酯酶和磷酸酶活力的影响

取食感虫品种的白背稻虱若虫体内羧酸酯酶(CarE)、酸性磷酸酶(AcpE)和碱性磷酸酶(AkpE)的活力明显高于取食抗虫品种的;取食中抗和中感品种的介于取食感虫品种和抗虫品种之间。水稻不同抗性品种对白背稻虱成虫及第二代若虫上述三种酶活力的影响也有类似倾向。     

野蚕黑卵蜂雌性内生殖器官的结构及其发育

报道了野蚕黑卵蜂成虫雌性内生殖器官的结构及其发育的系统观察结果。雌性成虫内生殖器官包括一对卵巢、两条侧输卵管、中输卵管、受精囊和附腺。成虫期卵巢生长速度随日龄是先增大后减小,但卵子随日龄是增大后并不下降,而且卵子成熟量一直保持较高水平,显示该蜂具有较强的生殖力。成虫期内其它生殖器官一般随日龄的增长而增大,达到一定程度后基本保持稳定。