Polymer composition analysis of plastic debris ingested by loggerhead turtles (Caretta caretta) in Southern Tyrrhenian Sea through ATR-FTIR spectroscopy

The ingestion of anthropogenic plastic debris by marine wildlife is widespread in the Mediterranean Sea. The endangered status (in the IUCN Red List) of Loggerhead turtle (Caretta caretta, Linnaeus, 1758) is a consequence of its vulnerability. In this study, macro-/meso-plastics (5-170 mm) collected from faeces of twelve loggerhead turtles rescued (live) in the Aeolian Archipelago (Southern Tyrrhenian Sea, Italy) were analyzed by size, weight, shape, color and polymer type through Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR). The defecation rate during hospitalization (7-14 days) varied among turtles (from 0.08 to 0.58). The mean number of plastic expulsions (2.7 ± 1.8 items for turtle) was higher during the 5th day of hospitalization (Kruskal-Wallis test, P = 0.01). However, the mean number of plastic-like items defecated during the common days of hospitalization did not vary among turtles (Kruskal-Wallis test, P > 0.05). All turtles were found to have ingested plastic. A total of 114 debris items were recovered from their faeces, 113 of which were identified as plastic. Their color was mostly white-transparent (64.9%) and light (19.3%). Shape was mainly fragments (52.6%), sheets (38.6%), followed by nylon, net-fragments, elastic plastic, foamed plastic and industrial granules (8.8%). Meso-plastics (5-25 mm) represented 72% of the total number of debris and were found more frequently in turtle with Curved Carapace Length (CCL) ≤ 60 cm (CCL = 30-60 cm, n = 5) than those with CCL >60 cm (CCL = 60-71 cm, n = 7). Plastic items were composed mainly of polyethylene (48.2%) and polypropylene (34.2%). Polypropylene (R² = 0.95, P < 0.001) and polyisoprene (R² = 0.45, P = 0.017) were more common in meso-plastics while polyethylene (R² = 0.44, P < 0.01) in macro-plastics. Finally, high-density polyethylene, polyvinyl chloride, polyamide and polyurethane were also found in some turtles. This study reveals high spreads of plastic contamination in faeces of both turtles with CCL ≤60 cm and CCL >60 cm, particularly vulnerable to the increasing quantity of floating plastic into their foraging sites highlighting the need of further research to associate debris ingestion with turtle diet and their size.

Phthalate esters (PAEs) concentration pattern reflects dietary habitats (δ13C) in blood of Mediterranean loggerhead turtles (Caretta caretta)

Phthalic acid esters (PAEs) are classified as endocrine disruptors, but it remains unclear if they can enter the marine food-web and result in severe health effects for organisms. Loggerhead turtles (Caretta caretta) can be chronically exposed to PAEs by ingesting plastic debris, but no information is available about PAEs levels in blood, and how these concentrations are related to diet during different life stages. This paper investigated, for the first time, six PAEs in blood of 18 wild-caught Mediterranean loggerhead turtles throughout solid-phase extraction coupled with gas chromatography-ion trap/mass spectrometry. Stable isotope analyses of carbon and nitrogen were also performed to assess the resource use pattern of loggerhead turtles. DEHP (12-63 ng mL^-1) and DBP (6-57 ng mL^-1) were the most frequently represented PAEs, followed by DiBP, DMP, DEP and DOP. The total PAEs concentration was highest in three turtles (124-260 ng mL^-1) whereas three other turtles had concentrations below the detection limit. PAEs were clustered in three groups according to concentration in all samples: DEHP in the first group, DBP, DEP, and DiBP in the second group, and DOP and DMP in the third group. The total phthalates concentration did not differ between large-sized (96.3 ± 86.0 ng mL^-1) and small-sized (67.1 ± 34.2 ng mL^-1) turtles (p < 0.001). However, DMP and DEP were found only in large-sized turtles and DiBP and DBP had higher concentrations in large-sized turtles. On the other hand, DEHP and DOP were found in both small- and large-sized turtles with similar concentrations, i.e. ~ 21.0/32.0 ng mL^-1 and ~ 7^.1/9.9 ng mL^-1, respectively. Winsored robust models indicated that δ¹³C is a good predictor for DBP and DiBP concentrations (significant Akaike Information criterion weight, AIC_wt). Our results indicate that blood is a good matrix to evaluate acute exposure to PAEs in marine turtles. Moreover, this approach is here suggested as a useful tool to explain the internal dose of PAEs in term of dietary habits (δ¹³C), suggesting that all marine species at high trophic levels may be particularly exposed to PAEs, despite their different dietary habitats and levels of exposure.

Diurnal preference, mood and the response to morning light in relation to polymorphisms in the human clock gene PER3

PER3 gene polymorphisms have been associated with differences in human sleep-wake phenotypes, and sensitivity to light. The aims of this study were to assess: i) the frequency of allelic variants at two PER3 polymorphic sites (rs57875989 length polymorphism: PER3 ⁴, PER3 ⁵; rs228697 SNP: PER3 ^C, PER3 ^G) in relation to sleep-wake timing; ii) the effect of morning light on behavioural/circadian variables in PER3 ⁴ /PER3 ⁴ and PER3 ⁵ /PER3 ⁵ homozygotes. 786 Caucasian subjects living in Northern Italy donated buccal DNA and completed diurnal preference, sleep quality/timing and sleepiness/mood questionnaires. 19 PER3 ⁴ /PER3 ⁴ and 11 PER3 ⁵ /PER3 ⁵ homozygotes underwent morning light administration, whilst monitoring sleep-wake patterns and the urinary 6-sulphatoxymelatonin (aMT6s) rhythm. No significant relationship was observed between the length polymorphism and diurnal preference. By contrast, a significant association was observed between the PER3 ^G variant and morningness (OR = 2.10), and between the PER3 ^G-PER3 ⁴ haplotype and morningness (OR = 2.19), for which a mechanistic hypothesis is suggested. No significant differences were observed in sleep timing/aMT6s rhythms between PER3 ⁵ /PER3 ⁵ and PER3 ⁴ /PER3 ⁴ subjects at baseline. After light administration, PER3 ⁴ /PER3 ⁴ subjects advanced their aMT6s acrophase (p < 0.05), and showed a trend of advanced sleep-wake timing. In conclusion, significant associations were observed between PER3 polymorphic variants/their combinations and both diurnal preference and the response to light.

Maternal immune activation results in complex microglial transcriptome signature in the adult offspring that is reversed by minocycline treatment

Maternal immune activation (MIA) during pregnancy has been linked to an increased risk of developing psychiatric pathologies in later life. This link may be bridged by a defective microglial phenotype in the offspring induced by MIA, as microglia have key roles in the development and maintenance of neuronal signaling in the central nervous system. The beneficial effects of the immunomodulatory treatment with minocycline on schizophrenic patients are consistent with this hypothesis. Using the MIA mouse model, we found an altered microglial transcriptome and phagocytic function in the adult offspring accompanied by behavioral abnormalities. The changes in microglial phagocytosis on a functional and transcriptional level were similar to those observed in a mouse model of Alzheimer's disease hinting to a related microglial phenotype in neurodegenerative and psychiatric disorders. Minocycline treatment of adult MIA offspring reverted completely the transcriptional, functional and behavioral deficits, highlighting the potential benefits of therapeutic targeting of microglia in psychiatric disorders.

Mapping elements distribution in carapace of Caretta caretta: A strategy for biomonitoring contamination in sea turtles?

This study analyzed the carapace distribution of Ca, Cd, Cr, Cu, Mg, Mn, Pb, Sb, U, V and Zn by GF-AAS and ICP-AES in one specimen of Caretta caretta from Mediterranean Sea. Calcium, Mg, Mn, Pb, U, Zn were mainly distributed in the central area while Cd, Cr, Cu, Sb, V in lateral areas. Cadmium, Cr, Mg, Mn, Sb, U and V were different between lateral areas. The different distribution may be related to several exposures during lifetime and/or the shell ossification during growth. Carapace may be a suitable matrix for metal biomonitoring, however, further studies are required to confirm these findings.

First Report of the Root Knot Nematode, Meloidogyne inornata, on Common Bean in Paraná State, Brazil

Common bean (Phaseolus vulgaris F.) is one of the most important crops in Paraná State, which is responsible for almost 10% of the Brazilian production (4). Root knot nematodes, Meloidogyne spp., are common parasites of this crop worldwide, but damage caused by Meloidogyne inornata has not been reported. During a survey of nematode species present on common bean fields in Paraná State, Brazil, galled root samples of cultivars Tuiuiú and Eldorado were submitted, in June 2012, in the Nematology Laboratory from IAPAR, collected in the municipalities of Araucária (25°35'34″S, 49°24'36″W) and Santana do Itararé (23°45'18″S, 49°37'44″W). Plants did not exhibit any above-ground symptoms. The specimens were identified through perineal patterns and esterase phenotypes of 20 adult females extracted from dissected roots (2,3). The population densities observed in the samples were 140 and 700 J2 and eggs per gram of roots, respectively, for both samples. Characteristics were consistent with those described for M. inornata. For example, perineal patterns of M. inornata showed a high dorsal arch, with smooth to wavy striae, similar to those of M. incognita; but no punctate markings between anus and tail terminus were observed. However, from the esterase electrophoresis we obtained the I3 (Rm = 0.83, 1.15, and 1.32) phenotype, typical of M. inornata, a species-specific phenotype used to differentiate this species from M. incognita (1). Moreover, the excretory pore of adult females was located 32.1 (± 5.4) μm from the anterior end, consistent with the M. inornata description (25 to 53 μm) (1). To the best of our knowledge, this is the first report of M. inornata parasitizing common bean roots. This finding has great importance for Brazilian agriculture, since this nematode may damage common bean plants and become an additional problem for this crop. Additional work is necessary in order to elucidate the losses caused by M. inornata on common bean. References: (1) R. M. D. G. Carneiro et al. Nematology 10:123, 2008. (2) P. R. Esbenshade and A. C. Triantaphyllou J. Nematol. 22:10, 1990. (3) K. M. Hartman and J. N. Sasser. Page 115 in: An Advanced Treatise on Meloidogyne, Volume II Methodology. K. R. Barker et al., eds. Raleigh: North Carolina State University Graphics, 1985. (4) MAPA. Feijão, Ministério da Agricultura, Brasil. Retrieved from http://www.agricultura.gov.br/vegetal/culturas/feijao September 05, 2012.

Sub-Chronic Oral Exposure to Iridium (III) Chloride Hydrate in Female Wistar Rats: Distribution and Excretion of the Metal

Iridium tissue distribution and excretion in female Wistar rats following oral exposure to iridium (III) chloride hydrate in drinking water (from 1 to 1000 ng/ml) in a sub-chronic oral study were determined. Samples of urine, feces, blood and organs (kidneys, liver, lung, spleen and brain) were collected at the end of exposure. The most prominent fractions of iridium were retained in kidney and spleen; smaller amounts were found in lungs, liver and brain. Iridium brain levels were lower than those observed in other tissues but this finding can support the hypothesis of iridium capability to cross the blood brain barrier. The iridium kidney levels rose significantly with the administered dose. At the highest dose, important amounts of the metal were found in serum, urine and feces. Iridium was predominantly excreted via feces with a significant linear correlation with the ingested dose, which is likely due to low intestinal absorption of the metal. However, at the higher doses iridium was also eliminated through urine. These findings may be useful to help in the understanding of the adverse health effects, particularly on the immune system, of iridium dispersed in the environment as well as in identifying appropriate biological indices of iridium exposure.

Human biomonitoring for metals in Italian urban adolescents: data from Latium Region

As a part of the activities of the first Italian human biomonitoring survey (PROBE - PROgramme for Biomonitoring general population Exposure), a reference population of adolescents, aged 13-15 years, was examined for their exposure to metals. The study included 252 adolescents living in urban areas, representative of Latium Region (Italy) and blood specimens were analyzed for metals (As, Be, Cd, Co, Cr, Hg, Ir, Mn, Mo, Ni, Pb, Pd, Pt, Rh, Sb, Sn, Tl, U, V and W) by sector field inductively coupled plasma mass spectrometry. The results obtained will improve the knowledge about the body burden in adolescents and are tentative reference values for Italian young people as a basis for risk evaluation deriving from urban/environmental exposure to metals.

The occurrence of chemical elements and POPs in loggerhead turtles (Caretta caretta): an overview

Chemical elements and persistent organic pollutants (POPs) are globally present in aquatic systems and their potential transfer to loggerhead marine turtles (Caretta caretta) has become a serious threat for their health status. The environmental fate of these xenobiotics may be traced by the analysis of turtles' tissues and blood. Generally, loggerhead turtles exhibited a higher metal load than other turtle species, this could be explained by differences in diet habits being food the main source of exposure. Literature shows that muscle, liver and kidney are most considered for the quantification of chemical elements, while, organic compounds are typically investigated in liver and fat. This paper is an overview of the international studies carried out on the quantification of chemical elements, polychlorinated biphenyls (PCBs), organochlorines (OCs) and perfluorinated compounds (PFCs), in tissues, organs and fluids of C. caretta from the Mediterranean Sea, the Atlantic and the Pacific Oceans.

Uncertainty evaluation in the analysis of biological samples by sector field inductively coupled plasma mass spectrometry. Part B: measurements of As, Co, Cr, Mn, Mo, Ni, Sn and V in human serum

This protocol was developed to estimate the uncertainty of measurements in the sector field inductively coupled plasma mass spectrometry analysis of As, Co, Cr, Mn, Mo, Ni, Sn and V in human serum by utilizing in-house validation data. The approach is outlined in the Eurachem/Citac Guide and other relevant publications. The results generated were the followings: (i) coefficients of regression >0.9995 over two orders of magnitude of metal concentration; (ii) method quantification limits between 0.05 µg/L (Cr, Mn) and 0.49 µg/L (As); (iii) mean trueness checked against a certified reference material between 95.4% (As) and 107.7% (Ni); (iv) repeatability better than 10.2% over the range 0.1-2.0 µg/L; (v) reproducibility better than 12.0% over the range 0.1-2.0 µg/L; and (vi) expanded uncertainty budget comprised between 14.7% (Mn) and 27.9% (Cr) over the range 0.1-2.0 µg/L.

Italian network for human biomonitoring of metals: preliminary results from two Regions

The Italian program for human biomonitoring (HBM) of chemical elements, PROgram for Biomonitoring of the Exposure (PROBE), started in 2008 with the aim to provide the knowledge about risk assessment of the Italian population following the environmental exposure to metals. The project is implemented through a HBM campaign for the production of data on 19 metals in the blood and serum of subjects living in different Italian Regions. The metals studied are: antimony, beryllium, cadmium, chromium, cobalt, iridium, lead, manganese, mercury, molybdenum, nickel, palladium, platinum, rhodium, thallium, tin, tungsten, uranium and vanadium. The first phase of the project has included the development and validation of laboratory protocols for the collection of fluids and quantification of metals. The second phase provides the HBM data expressed as the reference values (RVs) for the Italian population, i.e., as the level of metals in the general population not occupationally exposed. In this paper, the experimental protocols used for the maintenance of high standards of analysis and the RVs for metals in serum of inhabitants of two Italian Regions (Calabria and Umbria) are described.

Uncertainty evaluation in the analysis of biological samples by sector field inductively coupled plasma mass spectrometry. Part A: Measurements of Be, Cd, Hg, Ir, Pb, Pd, Pt, Rh, Sb, U, Tl and W in human serum

A protocol that utilises data (trueness/recovery, precision and robustness) from validation tests to calculate measurement uncertainty was described and applied to a sector field inductively coupled plasma mass spectrometry (SF-ICP-MS)-based method for the determination of Be, Cd, Hg, Ir, Pb, Pd, Pt, Rh, Sb, U, Tl and W in human serum. The method was validated according to criteria issued by international bodies such as AOAC, Eurachem and ISO and the uncertainty in the analytical measurements was estimated following the Eurachem/Citac guide. The methodology was based on dilution of human serum with water and analysis by serum-matched standard calibration. The method quantification limits ranged 0.02 microg/L (Tl, Ir) to 0.26 microg/L (Hg). The coefficients of regression were greater than 0.9991 over a range of two orders of magnitude of concentration. The mean trueness was 101% and the mean recovery on three levels of fortification (1-, 1.5-, and 2-times the baseline serum level) ranged between 93.3% and 106%. The maximum relative standard deviation values for repeatability and within-laboratory reproducibility were 12.8% and 13.5%. The method was robust to slight variations of some critical factors relevant to the sample preparation and SF-ICP-MS instrumentation. The relative expanded uncertainty over three levels of concentration ranged from 11.6% (Hg) to 27.6% (Pt), and the uncertainty on the within-laboratory reproducibility, which included factors such as time, analyst and calibration, represented the main contribution to the overall uncertainty.

Health risk evaluation associated to Planktothrix rubescens: An integrated approach to design tailored monitoring programs for human exposure to cyanotoxins

Increasing concern for human health related to cyanotoxin exposure imposes the identification of pattern and level of exposure; however, current monitoring programs, based on cyanobacteria cell counts, could be inadequate. An integrated approach has been applied to a small lake in Italy, affected by Planktothrix rubescens blooms, to provide a scientific basis for appropriate monitoring program design. The cyanobacterium dynamic, the lake physicochemical and trophic status, expressed as nutrients concentration and recycling rates due to bacterial activity, the identification/quantification of toxic genotype and cyanotoxin concentration have been studied. Our results indicate that low levels of nutrients are not a marker for low risk of P. rubescens proliferation and confirm that cyanobacterial density solely is not a reliable parameter to assess human exposure. The ratio between toxic/non-toxic cells, and toxin concentrations, which can be better explained by toxic population dynamic, are much more diagnostic, although varying with time and environmental conditions. The toxic fraction within P. rubescens population is generally high (30-100%) and increases with water depth. The ratio toxic/non-toxic cells is lowest during the bloom, suggesting a competitive advantage for non-toxic cells. Therefore, when P. rubescens is the dominant species, it is important to analyze samples below the thermocline, and quantitatively estimate toxic genotype abundance. In addition, the identification of cyanotoxin content and congeners profile, with different toxic potential, are crucial for risk assessment.

A study on metals content in patients with colorectal polyps

Data on metals involvement in colorectal polyps are scarce and fragmentary. The aim of this study was to examine whether the level of metals could be associated with risk of colorectal polyp development. The concentration of 15 chemical elements (Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg Mg, Mn, Pb, Se, Sr, and Zn) in 17 colorectal biopsies of healthy individuals, in 15 polypotic and corresponding nonpolypotic biopsies taken from the same individual, was evaluated. Concentration in polyps of metals such as Al, Ca, Mg, Mn, Pb, Sr, and Zn was unchanged both in unpaired and paired samples; elements such as Ba, Cd, and Hg were significantly lower and Fe was significantly higher both in individual and paired tissues. Cobalt, Cr, and Cu were significantly different only between polyps and the adjacent normal tissue area; Se showed a significant accumulation comparing polyps versus healthy tissues. The difference found in some elements between polyps and a control tissue provides an indication about the role of essential and nonessential elements in the early stage (polyps) in the colon carcinogenic process and encourages further studies to confirm the involvement of such elements in neoplastic processes.

Fungal infections in recipients of hematopoietic stem cell transplants: results of the SEIFEM B-2004 study--Sorveglianza Epidemiologica Infezioni Fungine Nelle Emopatie Maligne

BACKGROUND

The purpose of our study was to evaluate the incidence and outcome of invasive fungal infection (IFI) among patients who underwent autologous or allogeneic hematopoietic stem cell transplantation (HSCT) at 11 Italian transplantation centers.

METHODS

This cohort-retrospective study, conducted during 1999-2003, involved HSCT patients admitted to 11 tertiary care centers or university hospitals in Italy, who developed IFIs (proven or probable).

RESULTS

Among 3228 patients who underwent HSCT (1249 allogeneic HSCT recipients and 1979 autologous HSCT recipients), IFI occurred in 121 patients (overall incidence, 3.7%). Ninety-one episodes (2.8% of all patients) were due to molds, and 30 (0.9%) were due to yeasts. Ninety-eight episodes (7.8%) occurred among the 1249 allogeneic HSCT recipients, and 23 (1.2%) occurred among the 1979 autologous HSCT recipients. The most frequent etiological agents were Aspergillus species (86 episodes) and Candida species (30 episodes). The overall mortality rate was 5.7% among allogeneic HSCT recipients and 0.4% among autologous HSCT recipients, whereas the attributable mortality rate registered in our population was 65.3% (72.4% for allogeneic HSCT recipients and 34.7% for autologous HSCT recipients). Etiology influenced the patients' outcomes: the attributable mortality rate for aspergillosis was 72.1% (77.2% and 14.3% for allogeneic and autologous HSCT recipients, respectively), and the rate for Candida IFI was 50% (57.1% and 43.8% for allogeneic and autologous HSCT recipients, respectively).

CONCLUSIONS

IFI represents a common complication for allogeneic HSCT recipients. Aspergillus species is the most frequently detected agent in these patients, and aspergillosis is characterized by a high mortality rate. Conversely, autologous HSCT recipients rarely develop aspergillosis, and the attributable mortality rate is markedly lower. Candidemia was observed less often than aspergillosis among both allogeneic and autologous HSCT recipients; furthermore, there was no difference in either the incidence of or the attributable mortality rate for candidemia among recipients of the 2 transplant types.

Determination of 30 elements in colorectal biopsies by sector field inductively coupled plasma mass spectrometry: method development and preliminary baseline levels

An analytical procedure applicable to restricted sample sizes was developed and applied to the analysis of 30 chemical elements in colorectal biopsies of healthy patients. Acidic microwave digestion processed </=10 mg of tissue at 80 degrees C in 15-mL polystyrene liners. The digests were diluted to a volume of 2 mL with high-purity water and directly analyzed by sector field inductively coupled plasma mass spectrometry without further specimen handling. A careful selection of isotopes and instrumental resolution permitted the quantification in a single analytical sequence both of the elements present at parts per trillion and of those at parts per million. The accuracy calculated on BCR 184 ranged from 93.3-110%, the recoveries of the biopsy material was in the range 95.2-105%, the precision was <10%, and the blank levels were much below those expected in biopsy samples. The metal concentrations (on a dry-weight basis) in colorectal normal tissue showed a large range of variation: Ag, Au, Be, Bi, Co, Li, Sb, Tl, V, W and Zr were below 50 ng g(-1); As, Ba, Cd, Cr, Cs, Hg, Mo, Ni, Pb, Se and Sn were distributed from 100 to 500 ng g(-1); Al, Cu, Fe, Mn, Sr and Zn were from a few microg g(-1) to 100 microg g(-1); and Ca and Mg were at a level of 1000 microg g(-1). These data represent the first attempt to achieve an elemental profile in the colorectal mucosa of healthy patients as baseline level measurements for studies focused on the imbalance of chemical elements in diseased mucosa.

ELISA and LC-MS/MS methods for determining cyanobacterial toxins in blue-green algae food supplements

The use of natural products as a diet supplement is increasing worldwide but sometimes is not followed by adequate sanitary controls and analyses. Twenty samples of pills and capsules of lyophilised cyanobacteria (blue-green algae), commercialised in Italy as dietary supplements, were found positive at the Vibrio fischeri bioassay. Further analyses with ELISA and LC-MS/MS methods revealed the presence of four microcystin (MC) analogues, MC-LR, -YR, -LA, -RR and two demethylated forms of MC-RR. The highest total microcystin content was 4.5 and 1.4 microg g-1 in pills and capsules, respectively. The ELISA measurements, compared to the LC-MS/MS analyses, showed significantly lower concentrations of microcystins in pills, this confirming a possible ELISA underestimate of mixed microcystins, due to different sensitivities for some toxic analogues.

Microcystin diversity in a Planktothrix rubescens population from Lake Albano (Central Italy)

The cyanobacterium Planktothrix rubescens Anagnostidis & Komarek (previously Oscillatoria rubescens DC ex Gomont) is present in several Italian lakes and it is known to produce cyanotoxins. The dynamics and toxin production of P. rubescens population in Lake Albano, a volcanic crater lake in Central Italy, has been studied for 5 years (January 2001-April 2005). Winter-spring superficial blooms with frequent scums were observed every year. Total microcystin (MC) levels were measured from April 2004 to October 2005 by liquid chromatography-tandem mass spectrometry. MC levels up to 14.2mug/l were measured, with high concentrations found in summer at a 20-25m depth. The intracellular toxin content varied between 1.5 (surface, January 2004) and 0.21pg/cell (surface, May 2004). Six different MCs were detected, the most abundant being two desmethyl-MC-RR isomers. Of the 13 water wells monitored in the Lake Albano area, two of them showed MC contamination during winter, confirming the ability of these toxins to migrate through groundwater towards public water sources. These results highlight the need for further studies on the mobility and fate of these pervasive cyanobacterial toxins.

NK/T-cell lymphomas ‘nasal type’: an Italian multicentric retrospective survey

OBJECTIVE

To evaluate the clinical characteristics and outcome of NK/T-cell lymphoma 'nasal type' developed in Italian patients.

PATIENTS

Between 1997 and 2004, 26 new cases of NK/T-cell lymphoma 'nasal type' were diagnosed in 10 Italian Hematology institutions.

RESULTS

All patients were Caucasian, male/female ratio was 19/7, with a median age of 50 years (range 20-80). In 23 cases presentation at the onset was in the nasal cavity or adjacent structures, in two cases the lymphoma onset with skin lesions was followed successively by rhynopharyngeal dissemination, while the remaining case had bone marrow and lymph node involvement followed by oro-pharyngeal involvement. Regarding the stage of disease: 12 patients were in stage I; six in stage II; eight in stage IV. Diagnosis was based on the finding of a NK/T-cell phenotype at the histological and immunophenotypic examination of oropharyngeal or cutaneous lesions. All patients but one were treated with chemotherapy, alone in nine cases or associated to radiotherapy in 14 cases; two patients had chemotherapy, radiotherapy and surgery, while one patient underwent only surgery. Chemotherapy was anthracycline-based in 17 out of 25 cases. In those patients in whom radiotherapy was performed, radiation dosages ranged between 36 Gy and 47.5 Gy, with a median dosage of 40 Gy. Nine patients (34%) were responsive to the treatments: six patients obtained a complete remission and other three a partial remission. The remaining 17 patients resulted refractory or presented a limited response to therapy. The median disease-free survival was 14 months and the median overall survival time was 9 months.

CONCLUSION

The results of this retrospective survey confirmed that NK/T-cell lymphoma 'nasal type' is a very rare lymphoma in the Italian population, and it is characterized by a very bad prognosis. Due to the rarity of this disease, a standardized therapeutic approach is lacking. More data are needed to know the epidemiology of this kind of lymphoma in Europe.

Multiple resistance of acetolactate synthase and protoporphyrinogen oxidase inhibitors in Euphorbia heterophylla biotypes

Resistance to acetolactate synthase (ALS)-inhibiting herbicides in Brazil has been documented for six species. The probability to select biotypes of Euphorbia heterophylla (EPPHL) with multiple resistance increases in the same order of magnitude as the use of other herbicides belonging to only one mechanism of action. The objectives of this work were to evaluate the distribution of resistant populations (R) in the states of the Parana and Santa Catarina; to determine the existence of populations of EPHHL with multiple resistance to ALS and PROTOX inhibitors, and to confirm the occurrence of cross resistance to compounds of these mechanisms of action. Seeds of EPHHL of areas with suspected resistance had been sampled in 97 places during 2003. In the greenhouse experiment samples of each population were sprayed with imazethapyr or fomesafen, at only one rate. To identify the resistant ones they were sprayed with different levels of the herbicides imazethapyr and fomesafen. Later they were sprayed with diverse herbicides of the same mechanisms of action to confirm the multiple/cross resistance. There is widespread distribution in the region of populations with resistance to ALS inhibitors. Some biotypes demonstrated resistance to herbicides from the two mechanisms of action. The resistance factor (FR), or the relation of resistance between R and susceptible biotypes, confirms the existence of two biotypes of EPHHL with cross resistance to several herbicides inhibitors of ALS and PROTOX.

Successful treatment of Acremonium fungemia with voriconazole

We report two cases of Acremonium fungemia with proven involvement of the skin and probably of the lung in patients who were both undergoing chemotherapy, one for mantle cell lymphoma and the other for acute lymphoblastic leukemia. Both patients failed amphotericin B deoxycholate treatment and were successfully treated with voriconazole with very mild toxicity.

Voriconazole in the management of invasive aspergillosis in two patients with acute myeloid leukemia undergoing stem cell transplantation

The management of invasive aspergillosis in patients with hematological malignancies remains controversial. A major problem is how to manage patients who had invasive aspergillosis during remission induction and consolidation therapy and then undergo SCT. Indeed in these patients the mortality rate related to invasive aspergillosis recurrence remains unacceptably high. We report two cases of patients who underwent remission induction for AML, developed invasive aspergillosis during antifungal prophylaxis with itraconazole, failed amphotericin B deoxycholate and liposomal amphotericin B treatment, were successfully treated with voriconazole and eventually underwent SCT with voriconazole prophylaxis without reactivation of invasive aspergillosis.

Plasmodium falciparum signal sequences: simply sequences or special signals?

The malaria parasite, Plasmodium falciparum, synthesises and exports several proteins inducing morphological and biochemical modifications of erythrocytes during the erythrocytic cycle. The protein trafficking machinery of the parasite is similar to that of other eukaryotic cells in several ways. However, some unusual features are also observed. The secretion of various polypeptides was inhibited when P. falciparum-infected erythrocytes were incubated with Brefeldin A. Immunoelectron microscopy studies revealed substantial morphological changes in the endoplasmic reticulum following exposure of parasitised erythrocytes to the drug. Immunofluorescence studies of Brefeldin A-treated parasites suggest that polypeptide sorting to different intracellular destinations begins at the endoplasmic reticulum. The parasite also secretes polypeptides by a Brefeldin A-insensitive route that bypasses the classical endoplasmic reticulum-Golgi complex pathway.

Fludarabine in combination with cyclophosphamide or with cyclophosphamide plus mitoxantrone for relapsed or refractory low-grade non-Hodgkin's lymphoma

BACKGROUND AND OBJECTIVES

We report the activity of two combinations of fludarabine (FLU), one with cyclophosphamide (FLU/CY) and the second with CY plus mitoxantrone (FLU/CY/MITO). The aim of the study was to evaluate the activity and toxicity of these two schedules in patients with non-Hodgkin's lymphoma (NHL).

DESIGN AND METHODS

Twenty-two patients with recurrent low grade non-Hodgkin's lymphoma (LGL) received FLU/CY (FLU 25 mg/m(2) days 1 to 3, CY 300 mg/m(2) days 1 to 3), and 31 patients received FLU/CY/MITO (FLU 25 mg/m(2) days 1 to 3, CY 300 mg/m(2) days 1 to 3, mitoxantrone 10 mg/m(2) day 1). Patients received antibiotic oral prophylaxis during all treatments and growth factors (G-CSF) when grade III granulocytopenia (WHO scale) occurred.

RESULTS

Of the 53 patients, 31 achieved complete remission (CR) (58%) and 16 partial remission (PR) (30%). Response was similar in both arms of the study. After 3 courses, 77% of patients who achieved CR showed a complete disappearance of disease. Seventy-nine per cent of patients experienced granulocytopenia. Few patients had fever, all without infection. One patient died with fever of unknown origin three months after completion of six courses of treatment.

INTERPRETATION AND CONCLUSIONS

Both treatments were seen to be effective in recurrent low-grade NHL. Antibiotic prophylaxis with G-CSF support seems to reduce treatment-related infection.

Pfsbp1, a Maurer's cleft Plasmodium falciparum protein, is associated with the erythrocyte skeleton

Antibodies from hyperimmune monkey sera, selected by absorption to Plasmodium falciparum-infected erythrocytes, and elution at acidic pH, allowed us to characterize a novel parasite protein, Pfsbp1 (P. falciparum skeleton binding protein 1). Pfsbp1 is an integral membrane protein of parasite-induced membranous structures associated with the erythrocyte plasma membrane and referred to as Maurer's clefts. The carboxy-terminal domain of Pfsbp1, exposed within the cytoplasm of the host cell, interacts with a 35 kDa erythrocyte skeletal protein and might participate in the binding of the Maurer's clefts to the erythrocyte submembrane skeleton. Antibodies to the carboxy- and amino-terminal domains of Pfsbp1 labelled similar vesicular structures in the cytoplasm of Plasmodium chabaudi and Plasmodium berghei-infected murine erythrocytes, suggesting that the protein is conserved among malaria species, consistent with an important role of Maurer's cleft-like structures in the intraerythrocytic development of malaria parasites.

The transport of the histidine-rich protein I from Plasmodium falciparum is insensitive to brefeldin A

During its intraerythrocytic development, Plasmodium falciparum synthesizes several proteins that are exported beyond its membrane. Some of these secreted antigens are involved in the formation of protuberances or knobs, a major virulence factor, at the erythrocyte membrane. Various secreted malarial polypeptides, the transport of which is sensitive to brefeldin A, are translocated in vitro into dog pancreatic microsomes. We present evidence that the histidine-rich protein I (PfHRPI) is secreted by the parasite via a novel pathway, independent of the ER/Golgi apparatus. The secretion of PfHRPI was not blocked by incubation of parasite cultures at 15 degrees C and 20 degrees C or 37 degrees C in the presence of brefeldin A. PfHRPI was not translocated into microsomes in an in vitro translation-translocation cell-free system. Unlike other polypeptides from eukaryotic cells that bypass the ER/Golgi pathway and do not have a signal peptide, PfHRPI has an atypical signal sequence consisting of 21 amino acids, including eight positively charged residues followed by 11 hydrophobic residues. We also found that the unusually charged PfHRPI signal sequence diverts Exp-1, which is usually exported, away from the translocation machinery of microsomal membranes.

Novel secretory pathways in Plasmodium?

The secretion of proteins from intraerythrocytic stages of Plasmodium falciparum into the infected host cell is still poorly understood. A recent proposal that two distinct, mutually exclusive, secretory compartments may exist within the parasite cell has received much attention. Denise Mattei, Gary Ward, Gordon Langsley and Klaus Lingelbach here critically discuss the data on which this model is based, and then they address a more general question: to what extent are unusual aspects of protein secretion in Plasmodium unique among eukaryotic cells?

Limited genetic diversity of Plasmodium falciparum in field isolates from Honduras

The genetic diversity displayed by Plasmodiumfalciparum field isolates, the occurrence of variant forms of the parasite at different frequencies in different geographic areas, and the complexity of the infections represent major obstacles for the development of effective malaria control measures. However, since most of the existing studies have been performed in regions where P. falciparum transmission is high, little is known about the diversity and complexity of parasite populations circulating in areas of low malaria endemicity. We investigated the extent of genetic polymorphism in P. falciparum field isolates from Honduras, a region where its transmission is low and seasonal. Allelic diversity was analyzed in the highly polymorphic parasite genes encoding the merozoite surface proteins- (MSP-1) and -2 (MSP-2) and the glutamate-rich protein (GLURP) by the polymerase chain reaction. Gene polymorphism was also assessed in the EB200 region derived from the highly size polymorphic Pf332 gene. Limited size polymorphism was detected in all genes analyzed, with four and three variants for the MSP-1 and MSP-2 alleles, respectively, and two size variants for the GLURP and Pf332 genes. Moreover, based on the studied genetic markers, most infections consisted of only a few genetically distinct parasite clones. These results suggest that the P. falciparum parasite populations circulating in this region are genetically homogeneous and point to an association between the extent of parasite genetic diversity and the intensity of malaria transmission.

Expression and cellular localization of Trypanosoma cruzi type II DNA topoisomerase

Topoisomerases are enzymes that participate in many cellular functions involving topological manipulation of DNA strands. There are two types of topoisomerases in the cell: (a) type I topoisomerases; and (b) type II topoisomerases (topo II). Previously we have cloned and sequenced the gene encoding Trypanosoma cruzi topo II (TcTOP2). This study group has raised an antiserum against recombinant type II DNA topoisomerase (TctopoII) to study the expression of this gene during T. cruzi differentiation and to determine the cellular location of the enzyme. Western blot analysis showed that T. cruzi TctopoII is expressed in the replicative epimastigotes but not in the infective and non-replicative trypomastigotes. However, slot blot analysis of RNAs extracted from epimastigotes and metacyclic trypomastigotes showed that the mRNA encoding the enzyme is present in both developmental stages of the parasite. Confocal laser microscopy using the antiserum raised against recombinant TctopoII showed that the enzyme is located exclusively in the nucleus of the parasite. Similar results were obtained by immunofluorescence analysis of Crithidia fasciculata. However, monoclonal antisera against the corresponding enzyme extracted from C. fasciculata recognizes a kinetoplast protein in both T. cruzi and Crithidia.

Characterisation of PfSec61, a Plasmodium falciparum homologue of a component of the translocation machinery at the endoplasmic reticulum membrane of eukaryotic cells

Plasmodium falciparum secretes several proteins that cause changes in the erythrocyte membrane enabling it to survive within red blood cells. Little is known of the mechanisms involved in the secretion and targeting of parasite polypeptides to the various cell compartments. The P. falciparum gene homologous to the mammalian Sec61alpha, gene, which encodes a component of the translocation pore in the endoplasmic reticulum of eukaryotic cells, was characterised to investigate the translocation process in the parasite. PfSec61 is present as a unique copy in the parasite genome and was mapped to chromosome 13. It encodes a 40 kDa polypeptide, as shown by immunoblotting and immunoprecipitation of [35S]methionine metabolically-labelled parasite extracts. The deduced amino acid sequence of PfSec61 is 87% similar to the mammalian polypeptide, and the two proteins give similar hydropathy plots. These results strongly suggest that PfSec61 has the same topological orientation and functional role as Sec61alpha. Anti-PfSec61 antibodies were used to investigate the cellular location and kinetics of expression of the polypeptide in the parasite. Immunofluorescence confocal microscopy showed that PfSec61 was located in the parasite cytoplasm, close to the nucleus, in a position consistent with its being in the endoplasmic reticulum.

Biology of Giant Proteins of Plasmodium: Resolution on Polyacrylamide-Agarose Composite Gels

The malaria parasite Plasmodium falciparum that infects humans encodes several extremely large proteins with molecular masses in the hundreds of thousands to megadalton range. Studies on the structure, function and antigenicity of these ;giant proteins' are hindered by the inability to resolve them effectively in conventional polyacrylamide gels. In this report, Jochen Wiesner, Denise Mattei, Artur Scherf and Michael Lanzer describe a convenient gel system, based on a composite polyacrylamide-agarose matrix, which facilitates analysis of giant proteins.

Humoral immune response to the 72 kDa heat shock protein from Plasmodium falciparum in populations at hypoendemic areas of malaria in western Brazilian Amazon

The heat-shock protein Pf72/Hsp70-1 from the human malaria parasite Plasmodium falciparum has been suggested as a potential candidate antigen for a multivalent vaccine. We have investigated the prevalence and levels of IgG antibodies to the recombinant protein PfR44, derived from Pf72/Hsp70-1, in individuals from different age groups living in Candeias do Jamari, an Amazonian town characterized by unstable and hypoendemic malaria transmission. Blood were collected from a household-based random sample comprising 241 people and the sera were comparatively tested against recombinant antigen PfR44 and a detergent-soluble extract of P. falciparum (PfAg-T). The prevalence and levels of IgG antibodies to both recombinant and total P. falciparum antigens were positively correlated with cumulative exposure to malaria, as estimated by the age of the individuals and the duration of their stay in the study area. Nevertheless, correlations between antibody responses to Pf72/Hsp70-1 and the acquisition of protective anti-malarial immunity could not be derived from our data.

Immunogenicity and efficacy trials with Plasmodium falciparum recombinant antigens identified as targets of opsonizing antibodies in the naive squirrel monkey Saimiri sciureus

We have previously shown that Plasmodium falciparum recombinant antigens PfEB200, R23, and Pfi72 consistently inhibit opsonization of infected red blood cells by protective hyperimmune Saimiri sera, indicating that they present target epitopes involved in the phagocytosis of infected red blood cells. We report here an analysis of the immune response elicited in naive squirrel monkeys injected with the individual recombinant antigens or with a mixture of the three antigens combined with a synthetic peptide. In the three administration protocols investigated, there was no evidence for the production of antibody contributing to the phagocytosis of infected red blood cells, contrasting with the increase of opsonizing antibodies elicited by these antigens in monkeys with a prior (> or = 500 days) experience with malaria infection. However, the recombinant antigens were highly immunogenic, inducing specific antibody responses to P. falciparum and to the recombinant antigens. When the monkeys immunized with the antigen combination were challenged with blood-stage parasites, there was substantial protection: three of seven immunized animals self-cured and two others experienced a delayed peak of parasitemia. Taken together with our previous findings, these results suggest that PfEB200, R23, and Pfi72 constitute interesting vaccine candidates, and show that the presence of antibodies promoting phagocytosis of infected red blood cells is not a prerequisite for protection after immunization with these antigens in the Saimiri model.

Expressed var genes are found in Plasmodium falciparum subtelomeric regions

The antigenic variation and cytoadherence of Plasmodium falciparum-infected erythrocytes are modulated by a family of variant surface proteins encoded by the var multigene family. The var genes occur on multiple chromosomes, often in clusters, and 50 to 150 genes are estimated to be present in the haploid parasite genome. Transcripts from var genes have been previously mapped to internal chromosome positions, but the generality of such assignments and the expression sites and mechanisms that control switches of var gene expression are still in early stages of investigation. Here we describe investigations of closely related var genes that occur in association with repetitive elements near the telomeres of P. falciparum chromosomes. DNA sequence analysis of one of these genes (FCR3-varT11-1) shows the characteristic two-exon structure encoding expected var features, including three variable Duffy binding-like (DBL) domains, a transmembrane sequence, and a carboxy-terminal segment thought to anchor the protein product in knobs at the surface of the parasitized erythrocyte. FCR3-varT11-1 cross-hybridizes with var genes located close to the telomeres of many other P. falciparum chromosomes, including a transcribed gene (FCR3-varT3-1) in chromosome 3 of the P. falciparum FCR3 line. The relatively high level transcription from this gene shows that the polymorphic chromosome ends of P. falciparum, which have been proposed to be transcriptionally silent, can be active expression sites for var genes. The pattern of the FCR3-varT11-1 and FCR3-varT3-1 genes are variable between different P. falciparum lines, presumably due to DNA rearrangements. Thus, recombination events in subtelomeric DNA may have a role in the expression of novel var forms.

Cloning and characterisation of a gene from Plasmodium vivax and P. knowlesi: homology with valine-tRNA synthetase

We have previously described a lambdagt11 clone detected by immune screening with a monoclonal antibody (mAb) A12. This mAb is capable of completely blocking Plasmodium vivax transmission in the mosquito vector. An epitope recognised by A12 was mapped to six amino acids (aa) within the translated sequence of this clone. Here, we describe the complete sequence of the gene within which we mapped this epitope. Surprisingly, the translated sequence of the full-length open reading frame shows homology with that of valine-tRNA synthetases (Val-tRS) from other organisms. DNA cross-hybridisation with several of these species was observed by Southern blot. In addition, the corresponding gene has been obtained from the closely related simian malaria parasite, P. knowlesi. The two aa sequences show 66% identity and yet are very divergent from other Val-tRS sequences, apart from conserved blocks related to functional activity. Multiple sequence alignments reflect this dichotomy, as do predicted differences in antigenicity.

Immunogens containing sequences from antigen Pf332 induce Plasmodium falciparum-reactive antibodies which inhibit parasite growth but not cytoadherence

Immunogens based upon sequences from the P. falciparum asexual blood stage antigen Pf332 were assessed for their capacity to induce antibodies inhibiting parasite growth or cytoadherence of infected erythrocytes in vitro. Selection of the Pf332 sequences was based on their reactivity with the human monoclonal antibody (MoAb) 33G2 which inhibits parasite growth as well as cytoadherence in vitro. Octameric multiple antigen peptides (MAP) were assembled based upon either a trimer of the minimal epitope recognized by the MoAb, VTEEI, or a Pf332 sequence including that motif, SVTEEIAEEDK. A dimer of SVTEEIAEEDK was also expressed in Escherichia coli, genetically fused to ZZ, two IgG-binding domains of staphylococcal protein A. Rabbit antibodies elicited by the immunogens reacted with Pf332 in immunofluorescence and in ELISA with Pf332 peptides which were also recognized by MoAb 33G2. The MAP with branched (VTEEI)3 peptide induced the highest titres of P. falciparum-reactive antibodies. In contrast to MoAB 33G2, none of the polyclonal Pf332 reactive sera cross-reacted with repeat sequences of the malaria antigen Pf155/RESA. The polyclonal Pf332-reactive antibodies inhibited parasite growth efficiently but had no or very low inhibitory effect in a cytoadherence assay. Thus, while Pf332 may be an important target for parasite neutralizing antibodies its involvement in cytoadherence is unclear.

Karyotype analysis of virulent Plasmodium falciparum strains propagated in Saimiri sciureus: strain adaptation leads to deletion of the RESA gene

The squirrel monkey, Saimiri sciureus, is an important experimental model for the study of the human malaria parasite Plasmodium falciparum. A detailed karyotype analysis of four different P. falciparum strains propagated in S. sciureus was done using various subtelomeric antigen gene probes. We observed deletion of the complete RESA gene from chromosome 1 in all four strains. Interestingly, a loss of RESA was observed immediately upon adaptation to the squirrel monkey, suggesting that this DNA rearrangement is fundamental for the P. falciparum infection of S. sciureus erythrocytes. However, a RESA-specific gene probe hybridized with chromosome 1 of wild isolates from 28 different patients, indicating that this gene is maintained during infection of humans.

Induction of opsonizing antibodies after injection of recombinant Plasmodium falciparum vaccine candidate antigens in preimmune Saimiri sciureus monkeys

We have previously shown that Plasmodium falciparum recombinant antigens PfEB200, R23, and Pfi72 inhibit opsonization of infected erythrocytes by hyperimmune Saimiri sera, indicating that they contain target epitopes involved in the phagocytosis of infected erythrocytes. We have investigated in this study the immune response of Saimiri monkeys with previous experience of malaria infections (preimmune monkeys) after injection of these recombinant antigens, administered alone or simultaneously. The humoral response to the recombinant antigens was monitored by radioimmunoassay, and the response to P. falciparum blood stages was assayed by immunofluorescence. The relative proportion of protective versus nonprotective immunoglobulin subtypes was investigated by using 3A2/G6 and 3E4/H8 monoclonal antibodies, and the capacity of the antisera to promote in vitro phagocytosis of infected erythrocytes was evaluated. The antigens evoked in most cases a secondary-type antibody response, resulting in important increases in antigen-specific antibody titers and concomitantly in anti-P. falciparum titers. The ratio of 3A2/G6 to 3E4/H8 immunoglobulin subtypes varied with the immunogen used. Opsonizing antibodies were boosted in several animals, the most promising combination being the mixture of PfEB200 and R23 that induced long-lasting production in five of five animals. The detectable opsonizing activity appearing after immunization of the animals was antigen specific, as it was lost after adsorption of the recombinant antigens. The challenge of the animals with blood stage parasites confirmed previous findings showing a correlation between the presence of detectable opsonizing antibodies in serum and protection.

Immunization with the malaria heat shock like protein hsp70-1 enhances transmission to the mosquito

Mosquitoes fed on mice infected with Plasmodium yoelii after an immunization with the i72 recombinant form of the heat shock protein hsp70-1 developed significantly more oocysts than mosquitoes fed on controls. This effect was due to a marked increase in the relative numbers of gametocytes during the early stages of infection. A comparison of blood-induced and sporozoite-initiated infection showed that these gametocytes were derived from merozoites released from the liver. The stimulus for increased gametocyte production is unknown but is likely to be linked with antibody-dependent cellular cytotoxicity and associated cytokine responses.

Plasmodium falciparum: the Pf332 antigen is secreted from the parasite by a brefeldin A-dependent pathway and is translocated to the erythrocyte membrane via the Maurer's clefts

The transport of the megadalton protein Pf332 was studied during the asexual bloodstage development of Plasmodium falciparum. Four mouse monoclonal antibodies, produced against a recombinant polypeptide derived from the Pf332 protein, were used to analyze the kinetics of synthesis, the subcellular location, and transport of this giant molecule to the erythrocyte membrane. After parasite invasion of a red blood cell, the Pf332 antigen is first detected in young trophozoites at the parasitophorous vacuole membrane or in the cytoplasm of the erythrocyte as large vesicle-like structures. The number of vesicles increases during maturation of the parasite and thus forms a rim-like immunofluorescence pattern between the erythrocyte membrane and the parasitophorous vacuole at very late stages. The various anti-Pf332 antibodies react with the surface of erythrocytes infected with very mature parasites (segmenter stage 42-46 hr postinvasion). Immunoelectron microscopic analysis shows that the Pf332 antigen is transported in association with Maurer's clefts in the cytoplasm of the erythrocyte. This transport could be completely blocked by Brefeldin A, resulting in the accumulation of the antigen within the parasite. These data strongly suggest that the Pf332 antigen is exported to the erythrocyte cytoplasm via the classical Golgi secretory pathway.

Fusion between large phagocytic vesicles: targeting of yeast and other particulates to phagolysosomes that shelter the bacterium Coxiella burnetii or the protozoan Leishmania amazonensis in Chinese hamster ovary cells

This report examines the fusion of phagocytic vesicles with the large phagolysosome-like vacuoles induced in Chinese hamster ovary cells by the bacterium Coxiella burnetti or the Protozoan flagellate Leishmania amazonensis. Infection by these organisms is compatible with cell survival and multiplication. Fusion was inferred from the transfer of microscopically identifiable particles from donor to target vesicles. Donor vesicles contained heat-killed yeast, zymosan, beta-glucan or latex beads taken up by the host cells. Yeast and zymosan were also coated with Concanavalin A to increase their uptake by the cells (Goldman, R., Exp. Cell Res. 104, 325–334, 1977). Particle localization, routinely ascertained by phase-contrast microscopy, was confirmed by confocal laser fluorescence and by transmission electron microscopy. Coxiella vacuoles admitted all the particles tested and transfer took place whether the particles were given to the cells prior to or after infection. Transfer of uncoated or Concanavalin-A-coated yeast or zymosan was dependent on the number of particles ingested and on the incubation period (between 2 and 24 hours). Furthermore, the transfer step was quite efficient, since over 85% of the particles ingested entered Coxiella vacuoles at all particle to cell ratios examined. The fraction of uncoated or Concanavalin-A-coated yeast or zymosan transferred to Leishmania vacuoles was consistently lower and diminished at higher particle loads. In addition, only rarely did latex beads enter these vacuoles. The models proposed may be useful for the delineation of biochemical and molecular mechanisms involved in the fusion of large phagocytic vesicles and the modulation of the latter by cellular and pathogen-derived signals.

Interchromosomal exchange of a large subtelomeric segment in a Plasmodium falciparum cross

Duplications and interchromosomal transpositions of chromosome segments are implicated in the genetic variability of Plasmodium falciparum malaria parasites. One parasite clone, HB3, was shown to lack a subtelomeric region of chromosome 13 that normally carries a PfHRPIII gene. We show here that the chromosome 13 segment carrying PfHRPIII was replaced in HB3 by a duplicated terminal segment from chromosome 11. Mapping results indicate that the segment includes at least 100-200 kb of subtelomeric DNA and contains duplicated copies of the Pf332 and RESA-2 genes. We followed inheritance of this duplication in a genetic cross between the HB3 and another P.falciparum clone, Dd2, that is euploid for the Pf332, RESA-2 and PfHRPIII genes. Three types of progeny from the cross showed expected inheritance forms: a Dd2 euploid parent type, an HB3 aneuploid parent type, and a recombinant euploid type that carried PfHRPIII from Dd2 chromosome 13 and Pf332 from HB3 chromosome 11. However, a fourth euploid progeny type was also observed, in which the chromosome 13 segment from HB3 was transposed back to replace the terminus of chromosome 11. Three of 14 individual progeny were of this type. These findings suggest a mechanism of recombination from subtelomeric pairing and exchange between non-homologous chromosomes in meiosis.