Nondestructive biomarkers in ecotoxicology.

The aim of this article is to attempt a concise review of the state of the art of the nondestructive biomarkers approach in vertebrates, establishing a consensus on the most useful and sensitive nondestructive biomarker techniques, and proposing research priorities for the development and validation of this promising methodology. The following topics are discussed: the advantages of the use of nondestructive strategies in biomonitoring programs and the research fields in which nondestructive biomarkers can be applied; the biological materials suitable for nondestructive biomarkers and residue analysis in vertebrates; which biomarkers lend themselves to noninvasive techniques; and the validation and implementation strategy of the nondestructive biomarker approach. Examples of applications of this methodology in the hazard assessment of endangered species are also presented

Simultaneous production of raw starch degrading highly thermostable a-amylase and lactic acid by Lactobacillus fermentum 04BBA19

The widely used thermostable amylases were produced long time ago from Bacillus genus. Although, lactic acid bacteria (LAB) fermentation presents several advantages including the reduction of growth of pathogenic microorganisms, no study has yet reported thermostable amylases from lactic acid bacteria. An amylolytic LAB, Lactobacillus fermentum (04BBA19) isolated from starchy wastes of a soil sample from the western region of Cameroon was studied for amylase and lactic acid production. The bacterium exhibited maximal amylase and lactic acid production at temperature of 45°C, and within pH range of 4.0 to 6.5. Upon the optimization of various environmental and cultural conditions the yield of amylase and lactic acid reached 732.3±0.4 U/ml and 53.2±0.7 g/L respectively in fermented broth after 48 h of culture. The enzyme was identified as α-amylase, with a very high thermostability revealed by the retention of 100% of original activity after pre-incubation for 30 min at 80°C. The stability was improved significantly with the addition of 0.1% (w/v) CaCl2.2H2O; the half life of the enzyme in these conditions was 6 h at 80°C. Owing to its aptitude to exhibit a simultaneous production of thermostable amylase and lactic acid, L. fermentum (04BBA19) appeared as a potential candidate for the making of high density gruel from starchy material.Key words: Lactic acid bacteria, thermostable a-amylase, lactic acid, fermentation, high density gruel

Histochemical characterisation of oocytes of the swordfish <i>Xiphias gladius</i>

This work was partially funded by ICMAN.CSIC and the Spanish projects (MCYT/AGL2005-02478 and AGL2006-13777- CO3-O2/ACU). J.B. Ortiz-Delgado is supported by the Programa Ramón y Cajal (MEC, Spain)

Finland: Maintaining the fragile consensus

Peer reviewe

The In Vitro Effects of Aqueous and Ethanolic Extracts of the Leaves of Ageratum conyzoides (Asteraceae) on Three Life Cycle Stages of the Parasitic Nematode Heligmosomoides bakeri (Nematoda: Heligmosomatidae)

A comparative in vitro study was carried out to determine the ovicidal and larvicidal activity of aqueous and ethanolic extracts of Ageratum conyzoides (Asteraceae) leaves on the eggs (unembryonated and embryonated), first and second larval stages of Heligmosomoides bakeri. Four different concentrations (0.625, 1.25, 2.5, and 3.75 mg·mL−1) of both aqueous and ethanolic extracts were tested. Distilled water and 5% tween were used as negative controls in the bioassay. In fact, they did not affect development of eggs, hatching, and larval survival. The extract activities were dose dependent. The ethanolic extract was more potent against embryonation (39.6 ± 2.9%) than the aqueous extract (53.3 ± 10.9%) at the highest concentration (3.75 mg·ml−1). Both types of extracts killed larvae. Mebendazole proved more lethal (EC50 of 0.745 and 0.323 mg·mL−1, resp., for L1 and L2 larvae). The aqueous extracts were the least lethal (EC50 of 4.76 and 2.29 mg·mL−1, resp., for L1 and L2 larvae). The ethanolic extracts showed intermediate activity (EC50 of 1.323 and 1.511 mg·mL−1, resp., for L1 and L2 larvae). It is concluded that the ovicidal and larvicidal properties of aqueous and ethanolic extracts of Ageratum conyzoides leaves are demonstrated in this work

The Structure and Properties of Solar Active Regions and Quiet-Sun Areas Observed in Soft X-Rays with Yohkoh/SXT and in the Extreme-Ultraviolet with SERTS

We observed two solar active regions (NOAA regions 7563 and 7565), quiet-Sun areas, and a coronal hole region simultaneously with Goddard Space Flight Center's Solar EUV Rocket Telescope and Spectrograph (SERTS) and with the Yohkoh Soft X-ray Telescope (SXT) on 1993 August 17. SERTS provided spatially resolved active region and quiet-Sun slit spectra in the 280 to 420 A wavelength range, and images in the lines of He II λ303.8, Mg IX λ368.1, Fe XV λ284.1, and Fe XVI λλ335.4 and 360.8 SXT provided images through multiple broadband filters in both the full-frame imaging mode and the partial-frame imaging mode. The SERTS images in Fe XV (log Tmax = 6.33, where Tmax is the temperature which maximizes the fractional ion abundance in the available ionization equilibrium calculations, i.e., the formation temperature) and Fe XVI (log Tmax = 6.43) exhibit remarkable morphological similarity to the SXT images. Whereas the Fe XV and XVI images outline the loop structures seen with SXT, the cooler He II (log Tmax = 4.67) and Mg IX (log Tmax = 5.98) images outline loop footpoints. In addition, the Mg IX emission outlines other structures not necessarily associated with the hot loops; these may be cool (T 1 × 106 K) loops. From the spatially resolved slit spectra, we obtained emission-line profiles for lines of He II λ303.8, Mg IX λ368.1, Fe XIII λ348.2, Si XI λ303.3, Fe XIV λ334.2, Fe XV λ284.1, and Fe XVI λ335.4 for each spatial position. Based upon the spatial variations of the line intensities, active region 7563 systematically narrows when viewed with successively hotter lines, and appears narrowest in the broadband soft X-ray emission. The active region width (full width at half-maximum intensity) diminishes linearly with log Tmax; the linear fit yields an extrapolated effective log Tmax of 6.51 ± 0.01 for the X-ray emission. The most intense, central core straddles the magnetic neutral line. Active region and quiet-Sun one-dimensional temperature scans were derived from intensity ratios of spatially resolved SERTS slit spectral lines, and from coregistered SXT filter ratios. The highest plasma temperatures were measured in the most intense, central core of region 7563. The temperatures derived from Fe XVI λ335.4/Fe XV λ284.1 and Fe XVI λ335.4/Fe XIV λ334.2 vary significantly (based upon the measurement uncertainties) but not greatly (factors of less than 1.5) across the slit. The average log T values derived from the above two ratios for region 7563 are 6.39 ± 0.04 and 6.32 ± 0.02, respectively. Somewhat larger systematic variations were obtained from all available SXT filter ratios. The average active region log T values derived from the SXT AlMgMn/thin Al, thick Al/thin Al, and thick Al/AlMgMn filter ratios are 6.33 ± 0.03, 6.45 ± 0.02, and 6.49 ± 0.03, respectively. Active region and quiet-Sun one-dimensional density scans were derived from intensity ratios of spatially resolved SERTS slit spectral lines of Fe XIII and Fe XIV. The derived densities show neither systematic nor significant variations along the slit in either the active region or the quiet-Sun, despite the fact that the intensities themselves vary substantially. This indicates that the product of the volume filling factor and the path length (fΔl) must be greater by factors of 3-5 in the active region core than in the outskirts. Furthermore, the derived active region densities are ~2 times the quiet-Sun densities. This density difference is adequate to explain the factor of ~4 intensity difference in Fe XII and Fe XIII between the active and quiet areas, but it is not adequate to explain the factor of ~8 intensity difference in Fe XIV between the active and quiet areas. We attribute the latter to a greater fΔl in the active regions. Statistically significant Doppler shifts are not detected in region 7563 or in the quiet-Sun with any of the EUV lines

Mathematical modeling and nonstandard finite difference scheme analysis for the environmental and spillover transmissions of Avian Influenza A model

This work models, analyzes and assesses the impacts of environmental and spillover transmissions on Avian Influenza Virus (AIV) type A infection formulated in terms of nonlinear ordinary differential system that takes into account five spreading pathways: poultry-to-poultry; environment-to-poultry; poultry-to-human (spillover event); environment-to-human and poultry-to-environment. An in-depth theoretical and numerical analysis of the model is performed as follows. The basic reproduction number is computed and shown to be a sharp threshold for the global asymptotic dynamics of the submodel without recruitment of infected poultry. These results are obtained through the construction of suitable Lyapunov functions and the application of Poincaré-Bendixson combined with Lyapunov-LaSalle techniques. When the infected poultry is brought into the population, the model exhibits only a unique endemic equilibrium whose global asymptotic stability is established using the same techniques mentioned earlier. Further, the model is shown to exhibit a transcritical bifurcation with the value one of the basic reproduction number being the bifurcation parameter threshold. We further prove that during avian influenza outbreaks, the recruitment of infected poultry increases the disease endemic level. We show that the classical Runge-Kutta numerical method fails to preserve the positivity of solutions and alternatively design a nonstandard finite difference scheme (NSFD), which preserves the essential properties of the continuous system. Numerical simulations are implemented to illustrate the theoretical results and assess the role of the environmental and spillover transmissions on the disease.The University of Pretoria Senior Postdoctoral Programmehttps://www.tandfonline.com/loi/cdss202022-03-03hj2021Mathematics and Applied Mathematic

Effects of copper on larvae of the marbled crab Pachygrapsus marmoratus (Decapoda, Grapsidae): toxicity test and biochemical marker responses

The importance of trace elements in ecotoxicological investigations is a well-known issue when monitoring polluted areas such as commercial harbors. Copper represents one of the most common metal contaminants, often detected in these areas as it is widely employed in various fields and has many sources of inflow in the marine environment. Pachygrapsus marmoratus is a widespread intertidal crab species that has been extensively studied in ecology, ethology and population genetics. Ecotoxicological studies have also been performed, exclusively on the adult stage. In the present study we investigated the mortality and biochemical (oxidative stress and neurotoxicity) responses of P. marmoratus larvae exposure to environmental relevant concentration of copper. Results showed dose-dependent responses in terms of larval mortality, with a calculated LC50 value of 0.5 mg/L of Cu2+. The LC50 concentration was used as the starting point for subsequent biochemical response evaluation. Results also demonstrated dose-dependent activation of antioxidant systems assuming a compensatory antioxidant activity to prevent higher cellular damage when larvae were exposed to the highest concentrations of copper. Moreover, a significant enhancement of neurotransmitter activities was observed, assuming a possible direct interaction of copper with the enzymes or an increase of free copper ion aliquot into the cells.publishe

The experiences of autistic doctors: a cross-sectional study

IntroductionMedicine may select for autistic characteristics. As awareness and diagnosis of autism are growing, more medical students and doctors may be discovering they are autistic. No studies have explored the experiences of autistic doctors. This study aimed to fill that gap.MethodsThis is a cross-sectional study. A participatory approach was used to identify the need for the project and to modify a pre-existing survey for use exploring the experiences of autistic doctors.ResultsWe received 225 responses. 64% had a formal diagnosis of autism. The mean age of receiving a formal diagnosis was 36 (range 3–61). Most were currently working as doctors (82%). The most common specialties were general practice / family medicine (31%), psychiatry (18%), and anesthesia (11%). Almost half of those working had completed specialty training (46%) and 40% were current trainees. 29% had not disclosed being autistic to anyone at work. 46% had requested adjustments in the workplace but of these, only half had them implemented.Three quarters had considered suicide (77%), one quarter had attempted suicide (24%) and half had engaged in self-harm (49%). 80% reported having worked with another doctor they suspected was autistic, but only 22% reported having worked with another doctor they knew was autistic. Having never worked with a potentially autistic colleague was associated with having considered suicide.Most preferred to be called “autistic doctors” (64%). Most considered autism to be a difference (83%). Considering autism to be a disorder was associated with preference for the term “doctors with autism,” and with having attempted suicide.ConclusionAutistic doctors reported many challenges in the workplace. This may have contributed to a culture of nondisclosure. Mental health was poor with high rates of suicidal ideation, self-harm, and prior suicide attempts. Despite inhospitable environments, most were persevering and working successfully. Viewing autism as a disorder was associated with prior suicide attempts and a preference for person-first language. A neurodiversity-affirmative approach to autism may lead to a more positive self-identity and improved mental health. Furthermore, providing adequate supports and improving awareness of autistic medical professionals may promote inclusion in the medical workforce