Quantification of manganese and mercury in toenail in vivo using portable X-ray fluorescence (XRF)

Background and objective: Toenail is an advantageous biomarker to assess exposure to metals such as manganese and mercury. Toenail Mn and Hg are in general analyzed by chemical methods such as inductively coupled plasma mass spectrometry and atomic absorption spectrophotometry. In this project, a practical and convenient technology—portable X-ray florescence (XRF)—is studied for the noninvasive in vivo quantification of manganese and mercury in toenail.

Material and methods: The portable XRF method has advantages in that it does not require toenail clipping and it can be done in 3?min, which will greatly benefit human studies involving the assessment of manganese and mercury exposures. This study mainly focused on the methodology development and validation which includes spectral analysis, system calibration, the effect of toenail thickness, and the detection limit of the system. Manganese- and mercury-doped toenail phantoms were made. Calibration lines were established for these measurements.

Results: The results show that the detection limit for manganese is 3.65?μg/g (ppm) and for mercury is 0.55?μg/g (ppm) using 1?mm thick nail phantoms with 10?mm soft tissue underneath.

Discussion and conclusion: We conclude that portable XRF is a valuable and sensitive technology to quantify toenail manganese and mercury in vivo.     

Genital primordium of the free-living marine nematode Halichoanolaimus sonorus (Chromadoria,Chromadorida)

Summary

The genital primordium of the first stage juvenile (J1) of the free-living marine nematode Halichoanolaimus sonorus (Chromadorida: Selachinematidae) was studied using transmission electron microscopy. The primordium consists of four undifferentiated cells: two primordial germ cells (PGC) 5–6 μm in diameter and two somatic cells. The PGC have a large nucleus with nucleolus. The centriole was detected in close vicinity of the PGC nucleus. Most of the cell mitochondria are in close contact with the nuclear envelope. The mitochondria are interspersed by 0.2–0.3 μm particles of an electron-dense diffuse substance devoid of surrounding membrane. Both PGC are closely attached to each other and to the neighboring somatic cells of the genital primordium. The elongated somatic cells contain nuclei devoid of nucleoli; the cytoplasm is filled with free ribosomes and contains occasional cisternae of rough endoplasmatic reticulum (RER), Golgi bodies, mitochondria, and transparent vesicles. The genital primordium is separated by a narrow space from of the intestine (dorsally) and the somatic muscles (ventrally). The PGC of H. sonorous are devoid of typical P granules known for previously studied nematodes as distinct markers of germ line cell lineage. Perinuclear particles of dense diffuse substance found in PGC of H. sonorous could be considered as germ determinants analogous to P granules.     

Edge activators and a polycationic polymer enhance the formulation of porous voriconazole nanoagglomerate for the use as a dry powder inhaler

Purpose: Voriconazole has both low aqueous solubility and stability. We hypothesize that designing voriconazole in the form of a nano powder inhaler at a geometric diameter within 1–5?μm will enhance its stability and solubility. Therefore, we prepared nanoagglomerates of voriconazole which will collapse in the lungs to reform the nanoparticles.

Method: The nanoparticles were formulated using both stearic acid and sodium deoxycholate as edge activators. Osmogenic polycation polyethyleneimine (PEI) was used to form agglomerates of controllable size.

Results: Voriconazole nanoparticles and agglomerates showed a significant higher cumulative drug release than the pure powder (p?R^2?=^?0.95. Small-sized particles were formed (353?nm), while their zeta potential was ?30.7?mV. The agglomerates were 2.7?μm in size and their zeta potential was ?20.9?mV. The formation of porous agglomerates was confirmed using a transmission electron microscope. Cascade impactor was used to evaluate the aerodynamic properties of the nanoparticles and the agglomerates. The aerodynamic characterization of the nanoparticles and the agglomerates resulted in a significant smaller mass median aerodynamic diameter (MMAD) (p?p?p?p?Conclusion: The results suggest that using the combination of edge activators and diluted polycationic polymer solution provides porous voriconazole nanoagglomerates in a respirable range, which is proved successful in enhancing both the deposition and the dissolution of water insoluble-drugs in the lung.     

Ecological strategy for soil contaminated with mercury

Aims

The paper presents results from plot experiments aimed at the development of an ecological strategy for soil contaminated with mercury. Meadow grass (Poa pratensis) was tested on mercury contaminated soil in a former chlor-alkali plant (CAP) in southern Poland for its phytoremediation potential.

Methods

The stabilisation potential of the plants was investigated on plots without additives and after the addition of granular sulphur. Biomass production, uptake and distribution of mercury by plants, as well as leachates and rhizosphere microorganisms were investigated, along with the growth and vitality of plants during one growing season.

Results

The analysed plants grew easily on mercury contaminated soil, accumulating lower amounts of mercury, especially in the roots, from soil with additive of granular sulphur (0.5 % w/w) and sustained a rich microbial population in the rhizosphere. After amendment application the reduction of Hg evaporation was observed.

Conclusions

The obtained results demonstrate the potential of using Poa pratensis and sulphur for remediation of mercury contaminated soil and reduction of the Hg evaporation from soil. In the presented study, methods of Hg reduction on “hot spots” were proposed, with a special focus on environmental protection. This approach provides a simple remediation tool for large areas heavily contaminated with mercury.

     

Ultrastructure of grey mullet (Mugil cephalus,Linnaeus, 1758) spermatozoa as revealed from light,scanning and transmission electron microscopy

Spermatozoa morphology and fine structure were studied in the grey mullet, Mugil cephalus using light, scanning and transmission electron microscopy. Light microscopy observations indicate a semi‐cystic type of spermatogenesis in the testis. The electron microscopy micrograph showed that the spermatozoon of M. cephalus is uniflagellated (total length 5.78 ± 1.26 μm), differentiated into an ovoid‐shaped head without acrosome (1.80 ± 0.35 μm in length and 1.91 ± 0.30 μm in diameter), with a short midpiece and a long cylindrical flagellar tail (length 3.60 ± 0.50 μm). The midpiece is characterized by the presence of four to five vacuoles, a cytoplasmic canal, two centriole and two spherical mitochondria having a flat type of cristae. Chromatin granules of the nucleus form an electron‐dense homogeneous mass. The flagellum consists of nine peripheral microtubules and a central pair (9 + 2) surrounded by the plasma membrane with side fins. The results confirm that spermatozoa of M. cephalus are perciform or teleostean type II. Information generated from the present study will be useful in taxonomic classification, cryopreservation and breeding work.     

Secretory organelle biogenesis: Trichocyst formation in a ciliated protozoan

Summary— By classical electron microscopy and immunoelectron microscopy, the biogenesis of trichocyst secretory granules has been followed in the ciliated protozoan Pseudomicrothorax dubius. The very early pre-trichocysts form by fusion of bristle-coated, electron-dense vesicles (dense vesicles) with electron-translucent vesicles (clear vesicles), both of which originate in a well-developed trans-Golgi network (TGN). The pre-trichocyst grows by further fusion with dense and clear vesicles as well as with other pre-trichocysts until it reaches its maximum diameter of about 2 μm. Dense and clear vesicle formation from the TGN has been followed, and the fusion sequence of dense vesicles with the pre-trichocyst has been documented. The contents of the dense vesicles are the precursors of the trichocyst tip, which is composed of four arm-like rods, whereas the shaft precursors are supplied by the clear vesicles. The first evidence of trichocyst shaft formation is the appearance of a paracrystalline, dense core condensation center in the pre-trichocyst. Following shaft formation, the trichocyst tip forms by fusion and condensation of the dense arm precursors along each of the four sides of the shaft. Docking of the fully formed trichocyst in the cell cortex is described. Pre-trichocyst biogenesis in cells grown with and without Se is compared.     

Embryonic development and endosymbiont transmission mode in the symbiotic clam Lucinoma aequizonata (Bivalvia: Lucinidae)

Summary

Lucinoma aequizonata is a large lucinid clam which lives in reducing mud around 500 m deep. Adults harbor intracellular chemoautotrophic sulfur-oxidizing bacteria in specialized gill cells called bacteriocytes. The embryonic and early larval development of L. aequizonata is described by using light and scanning electron microscopy. Gametes were obtained by injection of 0.2ml of 4 mM serotonin solution in seawater into the posterior adductor muscle. The oocytes, 200 μm in diameter, are surrounded by a glycoprotein capsule which gives to the egg a total diameter of 500μm. The development which occurs at 10°C is slow. The first polar body is detected 2.5 h after contact between sperm and oocytes (T_o+2.5 h), and the first cleavage begins 10 h later (T_o+12.5 h). The following successive cleavages produce a nonciliated morula, then a ciliated gastrula which begins to rotate within the egg-capsule at T_o+4.5 days. At this stage, the first shell pellicle appears on the dorsal side of the embryo. At T₀+8 days, the trochophore larvae develop discrete ciliary bands which constitute the prototroch. Typical straight-hinge veligers, D-shaped larvae, hatch from the egg-capsule 12 days after fertilization. The newly hatched larvae are 240 μm in length and 200μm in height, and the straight hinge 150μm long. To elucidate the symbiont transmission mode, two symbiont-specific primers were designed and used in amplifications by PCR. This primer set was unsuccessful in amplifying symbiont DNA targets from mature gonads, spawned oocytes, eggs, and veligers whereas successful amplifications were obtained from symbiont-containing gill tissues. These data rule out the vertical transmission mode and strongly suggest that the symbionts are environmentally transmitted to the new host generation in L. aequizonata as for all tropical lucinids examined to date.     

Mercury bioremediation by mercury accumulating Enterobacter sp. cells and its alginate immobilized application

The effective microbial remediation of the mercury necessitates the mercury to be trapped within the cells without being recycled back to the environment. The study describes a mercury bioaccumulating strain of Enterobacter sp., which remediated mercury from the medium simultaneous to its growth. The transmission electron micrographs and electron dispersive X-ray analysis revealed the accumulation of remediated mercury as nano-size particles in the cytoplasm as well as on the cell wall. The Enterobacter sp. in the present work was able to accumulate mercury, without being engineered in its native form. The possibility of recovering the accumulated mercury from the cells is also indicated. The applicability of the alginate immobilized cells in removing mercury from synthetic and complex industrial effluent in a batch mode was amply demonstrated. The initial load of 7.3 mg l⁻¹ mercury in the industrial effluent was completely removed in 72 h. The cells immobilized in calcium alginate were similarly effective in the complete removal of 5 mg l⁻¹ HgCl₂ of mercury from the synthetic effluent in less than 72 h. The immobilized cells could be reused for multiple cycles.     

The role of photoreception in the swarming behavior of the copepod Dioithona oculata

The copepod Dioithona oculata forms dense swarms near mangrove prop roots that are centered around shafts of light penetrating the mangrove canopy. Swarms can be created in the laboratory within light shafts created with a fiber optic light pipe. Laboratory observations of swarming behavior were recorded using video cameras, and the swimming behavior of the copepods and density of the swarms were quantified using video‐computer motion and image analysis techniques. Swarm formation results from a combination of phototactic and klino‐kinetic behavior. Dark adapted copepods initially exhibit a photophobic response to a light shaft, but become positively phototactic within 3–5 min after exposure to the light. Copepod aggregation rates under the light fit a saturation model, suggesting that copepods are attracted independently to the swarm marker. Copepods reverse their swimming direction when they encounter light intensity gradients near the edge of a light shaft, which aids in maintaining the swarm. Swarm formation can occur in the laboratory at light intensities as slow as 0.1 μM photons m^‐2 s^‐1, which is similar to light intensities at dawn when they are first observed to form in nature. Swarm formation appears to have an endogenous rhythm, as copepods will not form swarms at night under a light shaft.     

Ultrastructure of spermatogenesis in Cerastoderma glaucum (Cardiacea) and Spisula subtruncata (Mactracea)

Summary

In Cerastoderma glaucum, Sertoli cells are rich in lipids, glycogen and lysosomes, and premeiotic cells exhibited nuage, a prominent Golgi complex and endoplasmic reticulum cisternae encircling the nucleus. The Golgi complex gives rise to proacrosomal vesicles during mid-spermiogenesis, and the round acrosomal vesicle, with a dense fibrillar core, migrates laterally while linked to the plasma membrane as it develops the subacrosomal material. In its final position, the vesicle becomes cap-shaped (0.6 μm) and differentiates into apical light and basal dense regions. The elongated and helicoidal nucleus (8–9.9 μm) has a thin tip (0.3 μm) that invades the subacrosomal space, and in the midpiece (0.8 μm) two of the four mitochondria extend laterally to the nucleus (1.5–2.1 μm). In Spisula subtruncata, Sertoli cells are rich in lipids, glycogen and phagocytosed sperm. Premeiotic cells exhibit nuage, a prominent Golgi complex that gives rise to proacrosomal vesicles from the leptotene stage and a flagellimi that is extruded at zygotene. The acrosomal vesicle forms during the round spermatid stage and differentiates into a large and dense basal region and an apical light region. It then migrates while linked to the plasma membrane by its apical pole. Development of the subacrosomal perforatorium is associated with nuage materials and endoplasmic reticulum vesicles. The mature cap-shaped (0.6 μm) acrosomal vesicle exhibits a large apical and irregular region with floccular contents and a basal dense region. The round nucleus becomes barrel-shaped (1.5 μm) and the midpiece (0.8 μm), with four mitochondria, contains a few glycogen particles.     

Soil aggregate and particulate C and N under corn rotations: responses to management and correlations with yield

Background

Soil aggregate and particulate organic matter (POM) C and N provide valuable insight into C cycling and storage, and are sensitive to management, but effect of these pools on corn yield is unknown.

Methods

Corn yield, N uptake, and aggregate and POM C and N at 0–5, 5–25 and 25–50 cm were measured and correlated in continuous corn (Zea mays L.) (CC), strip-till corn/soybean [Glycine max (L.) Merr.] (CS), and organically managed corn/soybean/wheat (Triticum aestivum L.) with green manure (CSW).

Results

The POM differed only at 0–5 cm, where greater POM mass was found in CS than CC and CSW. Lower POM-C and POM-N was found in CSW than CC and CS. Overall, CSW had fewer macroaggregates (>250 μm) and associated C and N than CC and CS, but free silt and clay (<53 μm) and microaggregates (53–250 μm) were enriched in C and N in CSW. Yield and macroaggregate-occluded C and N were negatively correlated. Yield and 5–25 cm free silt and clay C were positively correlated.

Conclusions

While organic matter in aggregate-occluded fractions is beneficial for soil C storage, it was correlated with lower grain yields, highlighting a potential tradeoff between yield and long-term C sequestration.

     

Progeny production in the periplasm of Thermosipho globiformans

Thermotogales are rod-shaped, Gram-negative, anaerobic, (hyper) thermophiles distinguished by an outer sheath-like toga, which comprises an outer membrane (OM) and an amorphous layer (AL). Thermosipho globiformans bacteria can transform into spheroids with multiple cells concurrently with AL disintegration during early growth; the cell is defined as the cytoplasmic membrane (CM) plus the entity surrounded by the CM. Spheroids eventually produce rapidly moving periplasmic ‘progenies’ through an unknown mechanism. Here, we used high-temperature microscopy (HTM) to directly observe spheroid generation and growth. Rod OMs abruptly inflated to form ~2 μm-diameter balloons. Concurrently, multiple globular cells emerged in the balloons, suggesting their translocation and transformation from the rod state. During spheroid growth, the cells elongated and acquired a large dish shape by possible fusion. Spheroids with dish-shaped cells further enlarged to ~12 μm in diameter. HTM and epifluorescence-microscopy results collectively indicated that the nucleoids of dish-shaped cells transformed to form a ring shape, which then distorted to form a lip shape as the spheroid enlarged. HTM showed that ‘progenies’ were produced in the spheroid periplasm. Transmission electron microscopy results suggested that the ‘progenies’ represented immature progenies lacking togas, which were acquired subsequently.

     

Two-hundred-years old shoots of the epiphytic moss Brotherella henonii preserved in a bark pocket of the conifer Cryptomeria japonica

Abstract

Schistidium flaccidum (De Not.) Ochyra is recorded as new to Britain from Snowdon, Wales. It may be distinguished from the other British species of the genus by its poculiform capsule, absence of peristome and small, dense tufts. Notes are given on its separation from Grimmia anodon, which it resembles more closely.     

The effect of mercury on the physiology of Rhytidiadelphus squarrosus (Hedw.) Warnst.

Abstract

Laboratory experiments have shown that low concentrations of mercury severely inhibit photosynthesis, temporarily increase respiration, reduce chlorophyll a and b concentrations and cause substantial loss of intracellular potassium from Rhytidiadelphus squarrosus. These changes have been interpreted as being due to mercury causing damage to the membrane systems of the cell.     

Limnology and macrophyte vegetation of a deep,clear limestone lake,Loch Borralie

Summary

A bathymetric survey shows Loch Borralie to have a maximum depth of 36 m. It is one of the most transparent lakes in Britain and is unstratified and poor in nutrients and phytoplankton, although the interstitial water of its calcareous muds is rich in nitrogen and phosphorus. Forty-four percent of the loch surface is densely colonised by macrophytes.

The littoral to 2 m bears very sparse Chara aspera var. lacustris and the zone from 2 to 4.5 m is dominated by tall Hippuris vulgaris, Myriophyllum spicatum and four Potamogeton spp., for which Chara and Nitella (principally C. globularis and N. flexilis) form an understorey. Three Potamogeton species persist to 6.5 m in an undulating Chara- Nitella ‘meadow’ which continues, alone, to between 12 and 15 m depth. Loch Borralie is the most deeply and possibly the most extensively colonised lake in the United Kingdom.     

Karyotype analysis of the southernmost South American species of Stemodia (Scrophulariaceae)

Abstract

The aim of the present study was to examine the somatic chromosomes of seven species of Stemodia (Scrophulariaceae). The karyotypes of Stemodia ericifolia (2n = 22 = 20m + 2 sm), S. hassleriana (2n = 22 = 20m + 2sm), S. hyptoides (2n = 22 = 20m + 2sm), S. hyptoides (2n = 44 = 40m + 4sm), S. lobelioides (2n = 44 = 40m + 4sm) and S. stricta (2n = 22 = 20m + 2sm) were analyzed for the first time. All the species studied showed a predominance of metacentric chromosomes and a lower proportion of submetacentric pairs. The chromosomes in all the species were found to be small with a mean chromosome length of 1.42 μm, varying from 0.77 μm in S. hyptoides (2n = 66) to 2.10 μm in S. lanceolata. The differences in the asymmetry of the karyotypes were small, for which it is possible to assume that the great diversification of the genus has been accompanied by very small changes in the structure of the chromosomes.     

Evaluation of toxic effects of heavy metals on unicellular algae. V-Influence of extracellular products on toxicity and on type of inhibition

Abstract

Results suggest that the toxicity of mercury and copper to two unicellular algae (Cyanidium caldarium and Chlorella saccharophila) can be decreased either through their subtraction from the culture medium by living or dead cells, or by the extracellular products.

The subtraction of the heavy metals tested manifests itself in each case by a shortening of the lag phase. Further, at least in the case of the combination Chlorella saccharophila-copper, a transition from type III inhibition (increased lag phase) to type II (decreased growth rate) as a results of an increase in the concentration of copper in the presence of extracellular products was observed.

This phenomenon was explained by the different toxic action exerted by copper in its ionic form (type III) as contrasted with copper combined in metalorganic compounds (type II).     

Ecdysteroid Titres and Cuticle Depositions in Embryos of the Dipteran Calliphora erythrocephala

Summary

Before the shortening of the germ band, embryos of Calliphora erythrocephala secrete an electron dense layer which resembles a thin atypical cuticle. After completion of the dorsal closure, a second, typical, cuticle is deposited. It is characterized by a thick procuticle and by the presence of hooked setae. This cuticle develops into the larval cuticle of the first instar.

We did not find in newly-laid eggs of Calliphora detectable amounts of either free or hydrolysable conjugated ecdysteroids. A marked rise in ecdysteroid concentrations, essentially attributable to free ecdysone and 20- hydroxyecdysone, occurs shortly before the deposition of the typical cuticle. After a transient decrease, the ecdysteroid titre rises again before hatching.

When eggs are mid-ligatured at blastula or early gastrula stages, the posterior embryonic half is able to build up a typical cuticle with hooked setae. This cuticulogenesis is therefore not dependent on the presence of the embryonic ring glands.