Fasciola gigantica: Cercarial shedding pattern from Lymnaea natalensis after long-term exposure to cadmium at different temperatures

Little is known about the response of Fasciola spp., inside its snail host to pollutant toxicity. The effect of long-term exposure of Lymnaea natalensis to 0.1 μg/l, 10 μg/l, or 100 μg/l cadmium (Cd) on the infection rates with F. gigantica, percentage of cercariae-shedding snails and cercariae shedding pattern was investigated. The snails were exposed to Cd for 7 days either pre-infection with single Fasciola miracidium or during the late pre-patent period of the infection. The possible interaction between metal exposure and acclimatization temperature was also studied in three ranges; 16-18 °C, 23-25 °C and 30-32 °C. Results clearly showed that host exposure to 100 μg/l Cd significantly affected the pattern of Fasciola development inside its snail host, and that the acclimatization temperature was a key factor affecting the role played by Cd. Pre-infection exposure to Cd caused a significant reduction in the infection rates where the effect was temperature-dependent. Post-infection exposure to Cd significantly increased the percentage of cercariae-shedding snails; the effect was temperature-independent. Interestingly, post-infection exposure significantly altered the differential cercarial output pattern, while no clear impact on the total was found. The alteration in the differential cercarial output was represented as a significantly higher proportion of floating metacercaria as compared to fixed ones and also higher proportion of dead cercariae which may directly reduce the transmission of Fasciola to the final host. The mechanisms of cadmium impact are briefly discussed.     

Morphology, developmental ultrastructure and ultracytochemistry of staminal hairs in Bulbine inflata (Asphodelaceae) in relation to function

Results of light and electron microscopy and preliminary ultracytochemical studies of the staminal hairs of Bulbine inflata at different stages of development are reported here. The staminal filaments are covered with yellow, unicellular, linear, erecto-patent hairs. These staminal hairs arise directly as single cell outgrowths from epidermal cells of the filament. The surface of each hair is patterned with helical wall thickenings in an anticlockwise direction. This wall is covered by a thick folded cuticle, and formed of a loosely fibrillar cellulose layer. The hair cell possesses a cytoplasm rich in organelles. Especially ribosomes are abundant. Plastids contain large starch grains and peripheral lipid droplets. The smooth endoplasmic reticulum cisternae (SER) encircle the plastids and mitochondria; it is extended in the cytoplasm along the hair length. These hairs have functions in flower pollination attracting pollinators visually, secreting specific substances, providing increased surface area, protecting the filaments and being involved in their movement and vibration.     

Isolation of anti-Candida albicans compounds from Markhamia obtusifolia (Baker) Sprague (Bignoniaceae)

An increase in clinical cases of Candidiosis globally as well as fungal resistance to drugs prompted the search for novel anti-Candida albicans agents from plant sources. Leaf extracts of Markhamia obtusifolia were screened for activity against C. albicans in vitro. An acetone extract obtained following serial exhaustive extraction contained mainly the active components with at least four active zones on the bioautogram. Bioassay guided fractionation of this extract led to the isolation of three compounds which inhibited the growth of three C. albicans strains. Based on spectroscopy studies (NMR and MS), the compounds were identified as 3β-hydroxyurs-12-en-28-oic acid, ursolic acid (1) 3β, 19α-dihydroxyurs-12-en-28-oic acid, pomolic acid (2) and 2β, 3β, 19α -trihydroxy-urs-12-en-28-oic acid, 2-epi-tormentic acid (3). The most active compound was 3β, 19α-dihydroxy-12-ursen-28-oic acid (2) with a minimum inhibitory concentration (MIC) value of 12.5 µg/mL for C. albicans isolated from dog and 25.0 µg/mL for C. albicans from cat and ATCC 90028 at 24 h following incubation. However, at 48 h of incubation MICs were > 400 µg/mL for all the three compounds isolated. This study indicated that M. obtusifolia could be a potential source of active principles against C. albicans.     

广西岩溶石山飞机草种群的繁殖特征

对广西岩溶石山3个典型群落(飞机草优势群落、黄荆条-飞机草混合群落和类芦-蔓生莠竹群落)中飞机草(Eupatorium odoratum)种群的繁殖特征进行了研究.结果表明:3个群落中飞机草的头状花序数为520～3281个m-2;种子产量为12941～74386粒m-2;头状花序的平均种子数为22～25粒;种子千粒重为...     

Reproductive biology and pollination of southeastern Brazilian Stanhopea Frost ex Hook. (Orchidaceae)

Reproductive biology and pollination of Stanhopea lietzei and Stanhopea insignis were studied in a semi-deciduous mesophytic forest in the Serra do Japi (SJ), and in the coastal plain of Picinguaba, both in the State of São Paulo, Brazil. Floral morphology, pollination, breeding system and fruit set of both species were investigated. S. lietzei and S. insignis are pollinator-specific, being pollinated by male bees of Eufriesea (Apidae, Euglossini), which collect the fragrance produced by pluricellular osmophores at the base of the saccate hypochile. S. lietzei and S. insignis were pollinated by Eufriesea pulchra and Eufriesea purpurata, respectively. Observations using substances present in the floral fragrance of both studied species as chemical baits were also performed. E. purpurata was attracted by benzyl alcohol, the major compound of the perfume of S. insignis, while E. pulchra was attracted by none of the compounds used. Both studied Stanhopea are self-compatible but pollinator dependent. Self-pollination, however, tends to be avoided by floral mechanisms. In experimental self- and cross-pollinations the proportion of fruit abortion was high and related to resource limitation. The reproductive success of S. lietzei and S. insignis was low as a consequence of deficient pollen transference while pollinator scarcity was the main factor.     

Setaria equina: In vivo effect of diethylcarbamazine citrate on microfilariae in albino rats

Although diethylcarbamazine citrate (DEC) is successful drug in eliminating human filariasis, yet, its mode of action is still debatable. Herein, the effect of DEC to treat albino rats infected with the animal filarial parasite Setaria equina was tested. Microfilarial (mf) counts and sections from liver, lung, kidney as well as spleen were investigated at different time points after treatment by light microscopy. After 45 and 300 min of treatment, a significant decrease in blood mf was observed accompanied by adherence of degenerated mf to both kupffer cells and leukocyte in liver sections. In lung sections, loss of sheath was observed at 45 min, while degeneration was observed at later time points. In kidney sections, more mf counts and less matrix were observed in the glomeruli at all time points after treatment. Degenerated mf were observed in spleen sections only at, late time point, 480 min after treatment. In conclusion, one of the possible mechanisms by which DEC reduces blood microfilarial count is trapping larvae in organs and killing them through cellular adherence.     

Reproductive performance of prepubertal Bos indicus heifers after progesterone-based treatments

The objective was to evaluate the effects of exogenous progesterone (P4) on reproductive performance of prepubertal Bos indicus heifers. Prepubertal Nelore heifers (n = 589; 24.0 ± 1.13 mo; 298.0 ± 1.89 kg; body condition score of 3.2 ± 0.26; mean ± SEM) were randomly assigned to receive, between experimental Days −12 and 0: no treatments (CIDR0; n = 113); a new intravaginal insert (CIDR) containing 1.9 g of P4 (CIDR1; n = 237); or a similar insert previously used three times, with each use occurring for 9 d (CIDR4; n = 239). An additional treatment group was pubertal heifers given 12.5 mg dinoprost tromethamine im on Day 0 (PGF; n = 346), and used as controls for evaluation of conception rates. On Day 0, transrectal palpation was done for uterine score evaluation (UtS; 1-3 scale), blood samples were taken for serum P4 concentrations, and follicle diameter (FD) was measured. The breeding season started on Day 1 and consisted of AI after detection of estrus between Days 1 and 45, and exposure to bulls between Days 46 and 90. There were effects of treatment (P < 0.05) on serum concentrations of P4 on Day 0 (0.37 ± 0.16, 2.31 ± 0.11, and 1.20 ± 0.11 ng/mL for CIDR0, CIDR1, and CIDR4, respectively; mean ± SEM), FD on Day 0 (9.45 ± 0.24, 9.72 ± 0.17, and 11.42 ± 0.16 mm), UtS on Day 0 (1.49 ± 0.06, 1.88 ± 0.04, and 2.24 ± 0.04), estrus detection rates at 7 d (19.5, 42.6, and 38.3%) and 45 d (52.2, 72.1, and 75.3%) of the breeding season, and on pregnancy rates at 7 d (5.3, 14.3, and 18.4%), 45 d (27.4, 39.2, and 47.7%) and 90 d (72.6, 83.5, and 83.7%) of the breeding season. Conception rate 7 d after the start of the breeding season was greater (P < 0.05) in heifers from the CIDR4 (46.8%) and PGF (43.8%) groups than in the CIDR0 (27.3%) and CIDR1 (33.7%) groups. In conclusion, exogenous P4 hastened puberty and improved pregnancy rates at the beginning of the breeding season in prepubertal Bos indicus heifers. Furthermore, previously used CIDR inserts were better than new inserts.     

Protective role of Mangifera indica, Cucumis melo and Citrullus vulgaris peel extracts in chemically induced hypothyroidism

An investigation was made to evaluate the pharmacological importance of fruit peel extracts of Mangifera indica (MI), Citrullus vulgaris (CV) and Cucumis melo (CM) with respect to the possible regulation of tissue lipid peroxidation (LPO), thyroid dysfunctions, lipid and glucose metabolism. Pre-standardized doses (200 mg/kg of MI and 100 mg/kg both of CV and CM), based on the maximum inhibition in hepatic LPO, were administered to Wistar albino male rats for 10 consecutive days and the changes in tissue (heart, liver and kidney) LPO and in the concentrations of serum triiodothyronine (T₃), thyroxin (T₄), insulin, glucose, α-amylase and different lipids were examined. Administration of three test peel extracts significantly increased both the thyroid hormones (T₃ and T₄) with a concomitant decrease in tissue LPO, suggesting their thyroid stimulatory and antiperoxidative role. This thyroid stimulatory nature was also exhibited in propylthiouracil (PTU) induced hypothyroid animals. However, only minor influence was observed in serum lipid profile in which CM reduced the concentrations of total cholesterol and low-density lipoprotein-cholesterol (LDL-C), while CV decreased triglycerides and very low-density lipoprotein-cholesterol (VLDL-C). When the combined effects of either two (MI + CV) or three (MI + CV + CM) peel extracts were evaluated in euthyroid animals, serum T₃ concentration was increased in response to MI + CV and MI + CV + CM treatments, while T₄ level was elevated by the combinations of first two peels only. Interestingly, both the categories of combinations increased T₄ levels, but not T₃ in PTU treated hypothyroid animals. Moreover, a parallel increase in hepatic and renal LPO was observed in these animals, suggesting their unsafe nature in combination. In conclusion the three test peel extracts appear to be stimulatory to thyroid functions and inhibitory to tissue LPO but only when treated individually.     

Toxoplasma gondii: Reproductive parameters in experimentally infected male rats

Toxoplasma gondii is a protozoan parasite that is globally widespread and infects man and animals. With the aim of studying the influence of toxoplasmosis on male reproductive parameters, we investigated sperm motility, concentration and morphology of male rats experimentally infected by T. gondii. The GT F1 strain of T. gondii tissue cysts were fed at a dose of 5 × 10³ tissue cysts per rat by oral gavage in an experimental group of 42 healthy adult male Wistar rats, while 42 male rats were used as controls. On days 10, 20, 30, 40, 50 and 60 post-inoculation (p.i.) 7 rats from each group were anesthetized. The body weight of each animal was recorded, then epididymis and testes were immediately removed, weighed and semen evaluation was undertaken. Weight of the right epididymis was significantly decreased on day 30 p.i., sperm motility was significantly decreased on days 10, 20, 30, 40, 50 and 60 p.i. and sperm concentration was significantly decreased on days 10, 30, 40 and 60 p.i. A marked increase of sperm abnormalities was noticed on days 30 and 40 p.i. No pathological lesions were detected either in the pituitary gland or the testes. In this study it was found that toxoplasmosis can affect main reproductive parameters in male rats, which are the most predictive of their fertilizing capacity.     

Reproductive behaviour of female Chorthippus biguttulus grasshoppers

Female grasshoppers of acoustically communicating species assume series of reproductive states that are associated with particular behaviours. Studies on laboratory populations of Chorthippus biguttulus (L.) revealed that females of this species lack the period of ‘passive copulatory readiness’, increase their attractiveness to males by sound production and mate multiple times before their first oviposition. In particular, female Ch. biguttulus display a period of ‘primary rejection’ after their imaginal moult during which they reject male mating attempts followed by a period of ‘active copulatory readiness’ in which they produce acoustic signals and may copulate with courting males. Female stridulation generally stimulated male mating activity and stridulating females attracted more male mating attempts than mute females in the same cage, indicating that males preferentially court females that signal ‘active copulatory readiness’. After receipt of a spermatophore, Ch. biguttulus females displayed periods of ‘secondary rejection’ followed by re-establishment of ‘active copulatory readiness’. Acoustic responses of females to male songs, an indicator of reproductive readiness, were significantly reduced until 2 days after mating and remained slightly reduced in comparison to pre-mating levels. Some females mated multiple times before their first oviposition and cycled between ‘secondary rejection’ and ‘active copulatory readiness’.     

Anxiolytic-like effect of Griffonia simplicifolia Baill. seed extract in rats

The seeds of Griffonia simplicifolia Baill., a tropical shrub native to West Africa, are rich in 5-hydroxy-l-tryptophan (5-HTP), a direct precursor in the synthesis of serotonin (5-HT). In spite of the modern therapeutic application of Griffonia simplicifolia seed extract in mood disorders, no scientific evidence has been provided till now. For this reason the aim of our study was to investigate the effect of Griffonia simplicifolia seed extract on anxiety behavior. Griffonia simplicifolia seed extract, dosed at 1, 5, 10 and 25 mg/kg, was orally administered in rats which were submitted to the dark-light test and open field test, 60 min after the treatment. In the dark-light test, the administration of the extract at the doses of 10 and 25 mg/kg was able to significantly increase the time spent in the light compartment (P < 0.05). In the open field test, the extract dosed at 5, 10 and 25 mg/kg induced an anti-tigmotactic effect, as indicated by a significant increase of time spent in the central area of the open field (P < 0.01). In conclusion these findings indicate that Griffonia simplicifolia seed extract exerts anxiolytic-like effect in rats and suggest its potential usefulness for the treatment of anxiety in humans.     

Modulatory role of Emblica officinalis fruit extract against arsenic induced oxidative stress in Swiss albino mice

Arsenic, an important human toxin, is naturally occurring in groundwater and its accumulation in plants and animals have assumed a menacing proportion in a large part of the world, particularly Asia. Epidemiological studies have shown a strong association between chronic arsenic exposure and various adverse health effects, including cardiovascular diseases, neurological defects and cancer of lung, skin, bladder, liver and kidney. The protective role of the fruits of Emblica officinalis (500 mg/kg b.wt.) was studied in adult Swiss albino mice against arsenic induced hepatopathy. Arsenic treated group (NaAsO₂, 4 mg/kg b.wt.) had a significant increase in serum transaminases and lipid peroxidation (LPO) content in liver, whereas significant decrease was recorded in hepatic superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and serum alkaline phosphatase activity. Combined treatment of Emblica and arsenic (pre and post) declined the serum transaminases and LPO content in liver whereas significant increase was noticed in SOD, CAT, GST and serum alkaline phosphatase activities. Liver histopathology showed that Emblica fruit extract had reduced karyolysis, karyorrhexis, necrosis and cytoplasmic vacuolization induced by NaAsO₂ intoxication. Thus it can be concluded that pre- and post-supplementation of E. officinalis fruit extract significantly reduced arsenic induced oxidative stress in liver.     

Recrudescence of Toxoplasma gondii infection in chronically infected rats (Rattus norvegicus)

The kinetics of Toxoplasma gondii infection reactivation in the brain and muscles was analyzed in this study to determine the preferred tissue by the parasite during immunosuppression. Two groups of Wistar rats (G1 and G2) were inoculated with 10⁴ bradyzoites of BTU10 strain (genotype I), p.o., and other two groups (G3 and G4) were inoculated with 0.9% saline solution. G2 and G4 were immunosuppressed with dexamethasone (DXM) and hydrocortisone sodium succinate (HSS). The presence of antibodies was researched in all groups through modified agglutination test (MAT) on days 0 and 21 p.i., and brain and muscle tissues of the rats were bioassayed in mice. G2 rats died at approximately 19.2 days after drug treatment, while G1 rats survived. The reactivation was initially observed in G1 brain and G2 muscles. Thus, the initial reactivation in muscles after immunosuppression allows doctors to save precious time to control the evolution of reactivated infection, preventing brain damage to the host.     

Septal pore complex morphology in the Agaricomycotina (Basidiomycota) with emphasis on the Cantharellales and Hymenochaetales

The ultrastructure of septa and septum-associated septal pore caps are important taxonomic markers in the Agaricomycotina (Basidiomycota, Fungi). The septal pore caps covering the typical basidiomycetous dolipore septum are divided into three main phenotypically recognized morphotypes: vesicular-tubular (including the vesicular, sacculate, tubular, ampulliform, and globular morphotypes), imperforate, and perforate. Until recently, the septal pore cap-type reflected the higher-order relationships within the Agaricomycotina. However, the new classification of Fungi resulted in many changes including revision of existing and addition of new orders. Therefore, the septal pore cap ultrastructure of more than 325 species as reported in literature was related to this new classification. In addition, the septal pore cap ultrastructures of Rickenella fibula and Cantharellus formosus were examined by transmission electron microscopy. Both fungi have dolipore septa associated with perforate septal pore caps. These results combined with data from the literature show that the septal pore cap-type within orders of the Agaricomycotina is generally monomorphic, except for the Cantharellales and Hymenochaetales.It appears from the fungal phylogeny combined with the septal pore cap ultrastructure that the vesicular-tubular and the imperforate type both may have arisen from endoplasmic reticulum. Thereafter, the imperforate type eventually gave rise to the perforate septal pore cap-type.     

Pollen tube reallocation in two preanthesis cleistogamous species, Ranalisma rostratum and Sagittaria guyanensis ssp. lappula (Alismataceae)

Pollen deposition on stigmas and pollen tube growth in two apocarpous species, Ranalisma rostratum and Sagittaria guyanensis ssp. lappula (Alismataceae), were examined with fluorescence microscopy. The reallocation of pollen tubes among pistils was observed in both species. The percentage of pollinated stigmas per flower was only 22.0% in R. rostratum and 51.0% in S. guyanensis, though the seed/ovule ratios are higher than 65% in both species. The number of pollen grains on each single stigma ranged from 0 to 96 in R. rostratum, and from 0 to 125 in S. guyanensis. When more than one pollen grain deposited on a stigma, all pollen tubes grew to the ovary, but only one of them turned towards the ovule and finally entered the nucleus. The other tubes grew through the receptacle tissue into ovules of adjacent carpels whose stigmas were unpollinated or pollinated later. The intercarpellary growth of pollen tubes could be a mechanism to increase the efficiency of sexual reproduction in an apocarpous gynoecium with low pollination on the pistils.     

RPB2 sequences reveal a close phylogenetic relationship between tetraploid Hordelymus and diploid Hordeum species in Triticeae (Poaceae)

The origin of Hordelymus genome has been debated for years, and no consensus conclusion was reached. In this study, we sequenced and analyzed the RPB2 (RNA polymerase subunit II) gene from Hordelymus europaeus (L.) Harz, and its potential diploid ancestor species those were suggested in previous studies. The focus of this study was to examine the phylogenetic relationship of Hordelymus genomes with its potential donor Hordeum, Psathyrostachys, and Taeniatherum species. Two distinguishable copies of sequences were obtained from H. europaeus. The obvious difference between the two copies of sequences is a 24 bp indel (insertion/deletion). Phylogenetic analysis showed a strong affinity between Hordeum genome and Hordelymus with 85% bootstrap support. These results suggested that one genome in tetraploid H. europaeus closely related to the genome in Hordeum species. Another genome in H. europaeus is sister to the genomes in Triticeae species examined here, which corresponds well with the recently published EF-G data. No obvious relationship was found between Hordelymus and either Ta genome donor, Taeniatherum caput-medusae or Ns genome donor, Psathyrostachys juncea. Our data does not support the presence of Ta and Ns genome in H. europaeus, and further confirms that H. europaeus is allopolyploid.