Hemoglobin Pigments Research Articles

Impact of some mineral fertilizers on the pulmonary and direct surface respiration of the allospecies of Planorbarius corneus superspecies (Gastropoda: Pulmonata: Planorbidae) from the Ukrainian water bodies

The vicariant genetic allospecies of the superspecies complex of the great ramshorn snail Planorbarius corneus s. lato, “western” and “eastern” – in Right Bank and Left Bank Ukraine, respectively, – are among the widespread and numerous gastropods in the Ukrainian river network. They possess two modes of respiration: pulmonary and surface (diffusive). The gas exchange in these snails is connected to the presence of the respiratory pigment hemoglobin in their internal liquid medium (hemolymph), which transports oxygen in their tissues and organs, and carbon dioxide to the lungs. We studied the features of impact of three mineral fertilizers widespread in Ukraine (nitrate, potassium and phosphate) used in concentrations measured in MPC 0.01 mg/L (0.5, 1, 2, 3) on the indexes of pulmonary and surface diffusive respiration in both P. corneus s. lato allospecies. Exposure of experimental individuals to 0.5 MPC-solutions of mentioned fertilizers does not affect them. The increase of toxicant concentration up to 2 MPC, however, is followed by an increase in respiratory activity (p≤0.05–0.001), but beyond that up to 3 MPC induces a significant decline (p≤0.001). Considered individually, the examined mineral fertilizers presented the following order by their impact on great ramshorns: nitrate > potassium > phosphate. The “eastern” allospecies appeared to be more sensitive and less durable for all aforementioned pollutants by both lung and direct diffusive respiration, compared to the “western” allospecies (p≤0.05–0.001).

A Method for Detecting Antioxidant Activity of Antioxidants by Utilizing Oxidative Damage of Pigment Protein.

A simple and effective method for detecting the antioxidant activity by utilizing oxidative damage of pigment proteins was developed. In this method, phycocyanin and bovine hemoglobin pigment proteins were used as substrates attacked by free radicals; AAPH was used as a free radical initiator; and Trolox as a positive control; and the fermentation products of Lactobacillus plantarum 793, phycocyanin hydrolysates, salmon skin collagen hydrolysates, and synthetic peptides PMRGGYHY and FCVLRP are antioxidants inspected in this study. Because of being attacked by free radicals, the absorbance of the pigment proteins at their characteristic absorption peak changes with time. By recording the time-varying curve at the characteristic absorption peak of the pigment protein in the blank/negative control sample, the Trolox positive control sample, and the samples of inspected antioxidants, the antioxidant activity could be calculated by using the specific equation. The linear detection ranges of Trolox in the phycocyanin assay and the bovine hemoglobin assay were 1-4μM and 4-24μM, respectively. Compared with the ORAC assay, the antioxidant activities of the samples measured by this method were slightly lower. The method proposed in this study reflects the protective effects of inspected antioxidants on pigment proteins, which could potentially serve as new biomarkers of oxidative damage processes.

Іnfluence of some heavy metals to the pulmonary and direct diffusive respiration of the great ramshorn Planorbarius corneus allospecies (Mollusca: Gastropoda: Planorbidae) from the Ukrainian river system

The vicaristic genetic allospecies (“western” and “eastern”) of superspecies complex Planorbarius corneus s. lato from Ukrainian river network have the combined bimodal respiration mode. These molluscs use their true lungs for atmospheric oxygen breathing, and the diffusive (surface) respiration is used for soluble oxygen consumption. Oxygen transportation to different tissues and organs and carbon dioxide from them to lungs occurs due to respiratory pigment hemoglobin in their liquid internal medium (hemolymph), circulating in vessels, lacunas and sinuses of these animals’ open circulatory system. The aim of present study was to clarify the features and difference levels of lung and surface respiration for “western” and “eastern” allospecies under the impact of heavy metal ions in water environment (MPC: 0.5, 1, 2, 3). It was established that the toxins could be ranged by their toxicity level for activation of molluscs’ respiratory function: Cu2+>Zn2+>Ni2+ >Mn2+. The “eastern” allospecies appeared to be more sensitive and less durable for all aforementioned toxins by both lung and direct diffusive respiration, comparing to the “western” allospecies.

In Silico Analysis of the Effects of Point Mutations on α-Globin: Implications for α-Thalassemia

Hemoglobinopathies are inherited diseases that impair the structure and function of the oxygen-carrying pigment hemoglobin (Hb). Adult Hb consists of two α and two β subunits. α-Thalassemia (α-thal) affects the genes that code for the α-globin chains, HBA1 and HBA2. Mutations can result in asymptomatic, mild or severe outcomes depending on several factors, such as mutation type, number of mutations and the location at which they occur. PredictSNP was used to estimate whether every possible single nucleotide polymorphism (SNP) would have a neutral or deleterious effect on the protein. These results were then used to create a plot of predicted tolerance to change for each residue in the protein. Tolerance to change was negatively correlated with the residue’s sequence conservation score. The PredictSNP data were compared to clinical reports of 110 selected variants in the literature. There were 29 disagreements between the two data types. Some of these could be resolved by considering the role of the affected residue in binding other molecules. The three-dimensional structures of some of these variant proteins were modeled. These models helped explain variants which affect heme binding. We predict that where a point mutation alters a residue that is intolerant to change, is well conserved and or involved in interactions, it is likely to be associated with disease. Overall, the data from this study could be used alongside biochemical and clinical data to assess novel α-globin variants.

Nondestructive sex-specific monitoring of early embryonic development rate in white layer chicken eggs using visible light transmission

ABSTRACT1. Sex-specific variations in early embryonic development rates may pre-empt later variations in embryonic development through to pipping and hatching. Given that erythropoiesis (blood production) can be equated with early embryonic growth rate, it was hypothesised that blood pigment haemoglobin can act as a specific spectral fingerprint for changes in growth rate. Moreover, by measuring longitudinal, rather than lateral, spectral transmission through the egg, a more consistent spectrum with a higher signal-to-noise ratio could be captured.2. Longitudinal visible transmission (T575/T598 ratio), which is sensitive to haemoglobin, was used to monitor sex-specific early embryonic development rate in white layer chicken eggs from d 0 to 8 of incubation. The sex of these eggs was subsequently confirmed two days after hatching.3. Embryonic development was detectable from d 3 (72 h) of incubation, 36 h earlier than previously reported lateral spectral measurements, supporting the greater sensitivity of longitudinal measurements.4. At d 3, the mean T575/T598 ratio for male embryos was significantly lower (P < 0.001) (i.e. higher absorbance of haemoglobin) than for female embryos, which was thought to be due to sex-differences in early embryogenesis. On the other hand, female embryos had a significantly lower (P < 0.05) mean T575/T598 ratio than male embryos at d 7 of incubation, presumably due to the combined effects of oestrogen synthesis receptors and enzymes on erythropoiesis in female embryos at this time.5. In conclusion, the proposed methodology has the sensitivity to differentiate sex-specific embryonic development rates during early incubation and the potentiality to advance precision incubation management and poultry research.

WBC Analysis using Data Augment Method and Convolutional Neural Network

WBC is a White Blood Cell or White Blood Corpuscle also known as Leucocytes. The normal count of WBC ranges from 4000 to 11000/mm3. It plays a vital role in the human body. Many diseases in human start with the abnormal balance of WBC, which acquire the part of immunity. To have adequate knowledge about WBC, we have to have a clinical test like blood count test which gives the count of RBC, hemoglobin, WBC, etc. RBC is otherwise known as Erythrocyte and it does not have a nucleus, with pigment hemoglobin. Due to the presence of this pigment, blood is red in color. In RBC, O2 and CO2 are transported in and out of the tissues. Recent research explains about diseases like cancer, allergy, breast cancer, etc are caused due to lack or abnormal WBC. This comes with the solution of finding the count of WBC in two types: Manually and automated way. In our paper, we are concentrating on collecting the WBC count using the Data augmentation method and Convolutional Neural Network.The Quality of image is improved in comparison with number of augmented images. This explains that we have 12500 sample images in the dataset in which 9957 samples are trained, validated on 2487 samples and training accuracy is high with increasing epoch value.

Canonical Correlation Analysis for Long-term Changes of Facial Images based on the Frequency of UV Protection, Physical and Psychological Features

In this paper, we analyze the relationship between impression of facial skin and skin component distribution by applying canonical coefficient analysis (CCA) to multiple physical and psychological features obtained from facial images. Based on the acquired relationship, we modulate the skin pigment features, and appearances of the face with arbitrary psychological features are reproduced. In our previous work, we applied principal component analysis (PCA) to the melanin pigment variation of the facial skin, and we obtained individual differences in it occurring over 7 years. In the previous method, as the factor causing individual difference, we considered the frequency of UV protection. However, actual skin appearance is thought to depend not only on melanin but also on several other factors. Therefore, in this study, we captured facial images of females aged from 10s to 80s at intervals of 12 years, and we obtained not only physical but also psychological features. As physical features, melanin and hemoglobin pigment and shading distributions, and the frequency of UV protection for 12 years were obtained. Psychological feature values were acquired as subjective evaluation. As a result of CCA on the physical features only, it was found that the whole face can be made lighter in appearance by performing UV protection every day continuously for 6 years or more. As a result on both physical and psychological features, pigment features greatly affecting the impression of the skin and multiple skin aging patterns were obtained. According to this result, the pigment features were modulated, and facial appearances with arbitrary psychological features were reproduced.

Partitioning of Cd, Zn and Fe in the Tissues and Cytosols of Blood Cockles (Anadara granosa) from the Gulf of Thailand

Anadara granosa is a bivalve blood cockle occurring abundantly in tropical estuarine intertidal sediments. The accumulation of Cd, Zn and Fe and their partitioning at the sub-cellular level in the cytosol has been investigated in the gills, digestive gland, body and foot of A. granosa from seven estuaries in the Gulf of Thailand. Cadmium and Zn were bioaccumulated predominantly in the gills with smaller concentrations distributed equally throughout the other tissues. Iron was present at relatively low concentrations in gills but was higher, and more evenly distributed, in the digestive gland, body and foot. The concentrations of metallothionein-like protein (MTLP) were found to be in the range 1–11 mg g−1 (dry weight) with the highest values being in the digestive gland at all sites. Partitioning of the metals in the cytosols between low molecular weight (LMW) compounds, MTLP and high molecular weight compounds (HMW) indicated that 16–39% of total Cd, 6.5–15% of total Fe and < 6% of total Zn were bound with MTLP. However, 23–27% of total Zn was bound with the HMW fraction, ascribed potentially to its association with the blood pigment haemoglobin (Hb). The metal-handling strategy, involving Zn, is likely important to blood cockles in supporting their uptake of dissolved oxygen in under-saturated tropical waters.

Hagfish pump some iron

Along with other nutrients, animals need trace metals to function. Iron, the oxygen-binding component in the blood pigment hemoglobin, is a critical trace metal and is usually absorbed through the gut. Mammals can alter iron metabolism in order to meet oxygen demand during periods of low environmental oxygen – hypoxia. However, it was unknown whether hagfish – a much more primitive group of animals that exhibit unusual tolerance to hypoxia – change their iron dynamics to achieve such resilience and whether they could take up iron from their environment. Knowing that hagfish can absorb some nutrients through their skin, Chris Glover, of Athabasca University, Canada, and colleagues from several other Canadian institutions set out to determine whether hagfish can take up iron across the skin; if so, how it might compare with gut uptake; and whether changes in iron transport during hypoxia contribute to the impressive hypoxia tolerance of these hardy fishes.To begin to answer their questions, the researchers measured iron transport across the skin and gut tissue of Pacific hagfish. Put simply, they exposed the external surface of each tissue to a solution containing radioactive iron at a range of concentrations and measured how much radioactivity entered a saline solution on the other side of the tissue after 2 h. They also measured how much radioactivity remained within the tissue itself.Glover and his colleagues found that the hagfish does take up iron through the skin – and at a higher rate than in the gut. Also, over all but the highest iron concentrations, the uptake in both tissue types initially increased with concentration and then reached a plateau. In addition, most iron absorbed by the skin remained in the skin, while iron absorbed by the gut tended to move across the tissue. The initial increase and subsequent uptake plateau indicate that specific transporter molecules are responsible for moving the iron in both tissues (as these molecules at some point reach a maximum transport capacity). However, the discrepancy in transport rates and in the iron's final destination suggests that each tissue handles iron differently.To find out whether hagfish alter iron transport during hypoxia – when the oxygen-binding metal is particularly essential – the researchers again measured iron transport, but this time on skin and gut from hagfish exposed to hypoxia for 24 h. They also analyzed the oxygen content of the fish blood, the red blood cell count and volume, the proportion of the blood made up of red blood cells and the blood hemoglobin content to determine whether hypoxia increases iron demand in hagfish as it does in mammals.Unexpectedly, hypoxia exposure did not significantly change iron transport in either the fish's skin or gut. Also, unlike in mammals, hypoxia did not appear to increase iron demand in the blood. These results suggest that changes in iron transport do not contribute to the hagfish's outstanding hypoxia tolerance and that the relative lack of change in blood parameters may preclude the need for any changes in iron transport in the first place.This study is the first to characterize trace metal transport in hagfish skin or gut and to identify iron transport in hagfish skin. It also paves the way for future research by raising more questions: what is the nature of the transporter; what happens to the iron in hagfish skin; and is skin iron transport ancient or adaptive? Clearly, these primitive hypoxia heroes are not ready to divulge all their secrets just yet; they've got them clenched in an iron fist – er, fin.

Pink teeth and the Dead: A review with reports of two cases

Pink teeth can occur in the living or as a postmortem phenomenon. In the context of forensic pathology, pink teeth are most commonly found in asphyxial deaths like drowning and strangulation; sudden and unnatural deaths, drug intoxications and carbon monoxide toxicity. However, their pathognomonic value is still doubtful as there is no obvious connection between the cause of death and this non specific phenomenon. The surrounding humid or wet environment appears to be essential in their formation. The process behind pink staining is hemolysis of erythrocytes and subsequent diffusion of hemoglobin pigment and/or its derivatives into the dentine tubules. A time delay is suggested between death and the occurrence of pink phenomenon. Two cases of putrefied corpses are described who died due to drowning and ligature strangulation, respectively. The autopsy revealed pink coloration of all the teeth in both cases which was more marked at their neck and cementum-enamel junction. The current view on the underlying chemical process, relation to the cause of death and the factors affecting the pink teeth phenomenon are explained with the help of both cases.

Determination of Human Hemoglobin Derivatives

The levels of the inactive hemoglobin (Hb) pigments [such as methemoglobin (metHb), carboxyhemoglobin (HbCO) and sulfohemoglobin (SHb)] and the active Hb [in the oxyhemoglobin (oxyHb) form] as well as the blood Hb concentration in healthy non pregnant female volunteers were determined using a newly developed multi-component spectrophotometric method. The results of this method revealed values of SHb% in the range (0.0727–0.370%), metHb% (0.43–1.0%), HbCO% (0.4–1.52%) and oxyHb% (97.06–98.62%). Furthermore, the results of this method revealed values of blood Hb concentration in the range (12.608–15.777 g/dL). The method is highly sensitive, accurate and reproducible.

Analysis of yellowish skin color from an optical image and the development of 3D Skin Chroma Diagram(™).

This study was conducted to define yellowish skin color, which is a major concern of Asian women, and to develop a 3D skin-pigment color model. A total of 22 Korean females were enrolled in this study. These women were asked to use a functional cosmetic product with whitening agents for 8weeks. We photographed the subsurface reflection of each subject's face using polarized light. The color of the subsurface reflection is a result of diffusive light transports that are attenuated by various skin pigments such as melanin, hemoglobin, and skin base colors. In this subsurface photo image, we eliminated the color effects of melanin and hemoglobin distribution by skin color analysis resulting in skin base color. Based on a variety of observed skin base colors from which the melanin and hemoglobin pigments have been removed, we defined a standard skin color for the entire subject group, and then, we gained a particular yellowish skin color by excluding the standard skin color from the skin base color again. After applying whitening cosmetic products, the amount of melanin and hemoglobin was reduced by 7.3% and 18.6%, respectively. Also, through using our new analysis method, yellowish skin color has been improved by 2.8%. We showed the improvement on 3D Skin Chroma Diagram(™) three-dimensionally. It became possible to diagnose yellowish color on human skin and to analyze the improvement in skin tone both quantitatively and visually.

An operative quantitative analysis of multispectral images of the eyeground

In the approximation of a four-layer model of the eyeground, we have studied the information content of photographs of the eyeground obtained in different spectral intervals from the visible range of the spectrum. We have shown that, under conditions of a priori uncertainty of all parameters of the eyeground that affect spectral fluxes of light multiply scattered by the eyeground, the two-dimensional distributions of the following parameters can be determined: (i) the contents of hemoglobin and macular pigment in the retina; (ii) the contents of melanin in the pigment epithelium and choroid; (iii) the degree of blood oxygenation; and (iv) the structural parameter of the retina, which characterizes the volume concentration of its effective scatterers. Based on results of a numerical simulation of the light-transfer process in the medium under study, we have determined regression relationships between parameters of the eyeground and spectral characteristics of its image and have proposed a method for the operative retrieval of parameter maps of the eyeground, which uses the determined regressions.

Aortic intimal staining in drowning

Case reportsCase 1: The body of an 85-year-old man was recoveredfrom within a submerged vehicle that he had accidentallydriven into a swimming pool. At autopsy, there was noevidence of decomposition with signs of immersionincluding ‘‘washerwoman’’ hands and feet (Figs. 1, 2),marked pulmonary congestion and edema (Fig. 3) andprominent differential staining of the aortic trunk comparedto the pulmonary outflow tract (Fig. 4). In addition therewas significant atherosclerotic narrowing of the left ante-rior descending coronary artery. No injuries were noted,toxicology was negative, and no other underlying organicdiseases were present which could have caused or con-tributed to death. Death was due to freshwater drowningcomplicating ischemic heart disease.Case 2: A 51-year-old man was observed to drown in ariver while attempting to rescue a model boat. At autopsy,there was no evidence of decomposition with signs ofimmersion including ‘‘washerwoman’’ hands with markedpulmonary congestion and edema and prominent differen-tial staining of the aortic trunk compared to the pulmonaryoutflow tract (Figs. 5, 6). No injuries were noted, toxicol-ogy was negative and no underlying organic diseases werepresent which could have caused or contributed to death.Death was due to freshwater drowning.DiscussionThe reported cases demonstrate differential staining of theintima of the aortic root compared to the pulmonary trunk infresh water drowning. This phenomenon, which has beenreported in the German literature as hemoglobin imbibitionof the intima, has been attributed to a hypo-osmolar effectwithinthebloodduetopassageoffreshwateracrossalveolarmembranes, or so-called hypo-osmolar hemolysis [1–4].AlthoughithasalsobeenmentionedinEnglishforensictexts[5–7],thisislesssoinrecentyears,resultinginitbecomingarelatively overlooked marker for drowning. While the clin-ical significance of the possible hydrostatic and osmoticeffects in fresh water drowning has been argued [8], thedemonstration of reduced levels of sodium in the left ven-tricle in fresh, compared to salt, water drowning would besupportive of the proposed mechanism [9].Hemolytic staining of the vascular intima is a well-recognized phenomenon in forensic practice, encounteredroutinely in association with decomposition and also incases with extensive burns or disseminated sepsis [10]. Inthese situations, however, the effect is usually generalized,involving most vessels. The color change of the intimaresults from breakdown of red blood cells with release oftheir iron-containing pigment hemoglobin which stains theadjacent vessel wall. A similar effect can be observed atpost mortem when vessels are left in contact with bloodthat has been lysed after mixing with water during dis-section [9]. Thus, any circumstance, condition or diseasewhich causes red cell membrane disruption can producethis effect. The striking aspect of this finding in fresh waterdrowning, however, is the geographic, focal nature of thestaining which involves only the aortic root [11]. Anyexplanation for a localized phenomenon such as this mustbe able to evoke a specific focal effect which is not present

Nonlinear microscopy looks beneath the surface of historic artwork

For the first time, it’s possible to create depth-resolved images of a painting without damaging it.

Blackwater fever like in murine malaria

Blackwater fever (BWF) is the term used to designate the occurrence of hemoglobin pigments in the urine of patients infected with malaria parasites. BWF is more often associated with Plasmodium falciparum infection in man. The pathogenesis of BWF has not been explained satisfactorily. In the present study, the clinical and pathological observations made upon CD1 mice infected with Plasmodium yoelii yoelii lethal strain with clinical signs of hemoglobinuria and acute renal failure were evaluated. From the 40 P. yoelii yoelii-infected mice, 14 presented hemoglobinuria. In the observations, it was emphasized that hemoglobinuria occurred in the animals 1-2days before they die. At 6days post-infection, infected hemoglobinuric mice (HM) exhibited clinical signs such as dark red urine, apnea, and evident oliguria and hematuria; urine microscopical examination showed very few red blood cells. The entire non hemoglobinuric infected mice had a high parasitemia preceding the time of death, while the HM parasitemia was just detectable. In HM, marked hepatosplenomegaly, anemia, and renal and hepatic dysfunction were observed with the blood chemistry analysis at 6days post-infection. Severe renal lesions were demonstrated in histopathological and scanning electron microscopy samples. Occlusion and necrosis of convoluted tubules were the main lesions found. The conditions required for the experimental production of hemoglobinuria in CD1 mouse infected by P. yoelii yoelii is still unknown. The clinical picture of a BWF, like in our rodents, was produced exclusively by the interaction between the parasite and its host. Results showed that hemoglobinuria in CD1 mice infected with P. yoelii yoelii and BWF in man infected with P. falciparum are similar in their pathogenesis.

HIGHLIGHTS FROM THE LITERATURE

HIGHLIGHTS FROM THE LITERATURE

Population structure and spatial distribution of Loripes lacteus (Linnaeus, 1758) in Varano lagoon, SE Italy

In Varano lagoon (Puglia, Italy) the bivalve Loripes lacteus (Linnaeus, 1758) constitutes the most abundant species among the organisms of the benthic macrofauna. This work presents the results of five years (from 2001 at 2006) of observations on the abundance, size/age population structure and spatial distribution of this species within the basin (6500 ha). L. lacteus is one of the most common and frequent bivalve species in Mediterranean lagoons. It typically occurs in reduced sediments where it is able to live at low oxygen concentration due to a particular respiratory pigment haemoglobin. Lucinid bivalves house symbiotic, sulphur-oxydizing chemoautotrophic bacterias in their gills, which contribute substantially to their nutrition. The design was to perform two sampling campaignes on yearly basis during the intermediate seasons (Spring and Autumn), when possible. Each sampling was realized collecting 53 sampling units taken from 53 stations distributed regularly over the lagoon surface. Each sampling unit consisted in all the individuals contained in a solid 15 x 15 x 20 cm of sediment and held on 1 mm mesh. Growth patterns were determined with the Bhattacharya method which uses modal progression analysis from size frequency distribution. The results showed a spatial distribution of L. lacteus which occurred in patches and changed among samples. The population analysis showed two modal classes for each sampling time. L. lacteus is an “r” strategy species with small size, brief life cycle, with great capacity of recovery after environmental crises.

The Role of Nramp1 in Erythrophagocytosis.

Erythrocytes contain the majority of the body's iron in the form of heme, a component of the red blood cell pigment hemoglobin. Erythrocytes transport oxygen bound to hemoglobin from the lungs to the tissues, and become progressively more damaged as they age. Macrophages are responsible for the detection and degradation of these senescent red blood cells, and play a central role in the recycling of hemoglobin-derived iron via transferrin to the bone marrow in order for erythropoiesis to occur. This recycling process, and the influence of inflammatory mediators on it, are poorly understood. Nramp1 is a protein expressed within macrophages, and is an iron transporter discovered to be mutated in mice susceptible to tuberculosis and leprosy infections. As Nramp1 localizes to phagosomal membranes following phagocytosis, we speculate that Nramp1 may play a role in the recycling of hemoglobin-derived iron following the internalization of effete erythrocytes. To test this possibility, we have utilized a model of erythrophagocytosis using both Nramp1 replete and deficient RAW264.7 murine macrophages, and macrophages elicited from wild type and Nramp1-knockout 129SV mice. We have found that Nramp1 protein is increased in primary macrophages following internalization of opsonized murine erythrocytes. This increase peaks at 6 hours of erythrocyte exposure, and decreases to baseline levels overnight. Our model of erythrophagocytosis did not induce macrophage activation as no nitric oxide production was observed. This therefore discounts the possibility that inflammatory factors are the cause of the increase in Nramp1 protein levels. Using the fluorescent iron-binding probe, calcein, we monitored changes in the macrophage labile iron pool (LIP) following erythrocyte loading. This transit pool of loosely bound, chelator-accessible iron is thought to reflect the overall iron status of the cell. We have found that, following erythrophagocytosis of opsonized murine erythrocytes, Nramp1-replete RAW264.7 macrophages experience a greater-fold increase in labile iron as compared to Nramp1-deficient macrophages. Furthermore, we have also found that primary peritoneal macrophages elicited from wild type 129SV mice phagocytose more erythrocytes when compared to macrophages elicited from their Nramp1-knockout counterparts. Interestingly, we have also observed that treatment with erythropoietin, the hormone responsible for the promotion of erythrocyte precursor survival and ultimately the increase in red blood cell production, resulted in a modest increase in Nramp1 protein levels. Our observations show distinct differences in iron metabolism between Nramp1 replete and deficient macrophages undergoing erythrophagocytosis. We speculate that Nramp1 may serve to promote a more efficient intracellular transport of iron following red blood cell engulfment.

Ameliorating Effect of Chloride on Nitrite Toxicity to Freshwater Invertebrates with Different Physiology: a Comparative Study Between Amphipods and Planarians

High nitrite concentrations in freshwater ecosystems may cause toxicity to aquatic animals. These living organisms can take nitrite up from water through their chloride cells, subsequently suffering oxidation of their respiratory pigments (hemoglobin, hemocyanin). Because NO(2)(-) and Cl(-) ions compete for the same active transport site, elevated chloride concentrations in the aquatic environment have the potential of reducing nitrite toxicity. Although this ameliorating effect is well documented in fish, it has been largely ignored in wild freshwater invertebrates. The aim of this study was to compare the ameliorating effect of chloride on nitrite toxicity to two species of freshwater invertebrates differing in physiology: Eulimnogammarus toletanus (amphipods) and Polycelis felina (planarians). The former species presents gills (with chloride cells) and respiratory pigments, whereas in the latter species these are absent. Test animals were exposed in triplicate for 168 h to a single nitrite concentration (5 ppm NO(2)-N for E. toletanus and 100 ppm NO(2)-N for P. felina) at four different environmental chloride concentrations (27.8, 58.3, 85.3, and 108.0 ppm Cl(-)). The number of dead animals and the number of affected individuals (i.e., number of dead plus inactive invertebrates) were monitored every day. LT(50) (lethal time) and ET(50) (effective time) were estimated for each species and each chloride concentration. LT(50) and ET(50) values increased with increases in the environmental chloride concentration, mainly in amphipods. Results clearly show that the ameliorating effect of chloride on nitrite toxicity was more significant in amphipods than in planarians, likely because of the absence of gills (with chloride cells) and respiratory pigments in P. felina. Additionally, this comparative study indicates that the ecological risk assessment of nitrite in freshwater ecosystems should take into account not only the most sensitive and key species in the communities, but also chloride levels in the aquatic environment.