Molecular surveillance detects high prevalence of the neglected parasite Mansonella ozzardi in the Colombian Amazon

Mansonellosis is an undermapped insect-transmitted disease caused by filarial nematodes that are estimated to infect hundreds of millions of people globally. Despite their prevalence, there are many outstanding questions regarding the general biology and health impacts of the responsible parasites. Historical reports suggest that the Colombian Amazon is endemic for mansonellosis and may serve as an ideal location to pursue these questions in the backdrop of other endemic and emerging pathogens. We deployed molecular and classical diagnostic approaches to survey Mansonella prevalence among adults belonging to indigenous communities along the Amazon River and its tributaries near Leticia, Colombia. Deployment of a loop-mediated isothermal amplification (LAMP) assay on blood samples revealed an infection prevalence of ∼40% for Mansonella ozzardi . This assay identified significantly more infections than blood smear microscopy or LAMP assays performed using plasma, likely reflecting greater sensitivity and the ability to detect low microfilaremias or occult infections. Mansonella infection rates increased with age and were higher among males compared to females. Genomic analysis confirmed the presence of M. ozzardi that clusters closely with strains sequenced in neighboring countries. We successfully cryopreserved and revitalized M. ozzardi microfilariae, advancing the prospects of rearing infective larvae in controlled settings. These data suggest an underestimation of true mansonellosis prevalence, and we expect that these methods will help facilitate the study of mansonellosis in endemic and laboratory settings.

P-549 Paraclinical and spermogram evaluation of infertile males with balanced chromosomal rearrangements referred to Royan institute from 2009-2021

Study question

Whether balanced chromosomal rearrangements are associated with altered semen parameters/increased DNA Fragmentation Index (DFI), are the common breakpoints related to male infertility in patients ?

Summary answer

Balanced chromosomal rearrangements is associated with abnormal semen parameters and increased DFI in carriers. Chromosomes 9,1,3 showed the highest incidence of chromosomal rearrangement

What is known already

Among many factors, balanced chromosomal rearrangements are thought to be one of the major genetic factors influencing male infertility which can cause disorders related to spermogram, DNA fragmentation, increased risk of miscarriage and ART failure. Finding common chromosomal breakpoints in infertile men carrying balanced chromosomal translocations is significant since these patients usually possess normal clinical features. Numerous studies have been performed on the various chromosome translocations. However, there has not been any report on the common breakpoints in balanced chromosomal abnormalities related to male infertility in Iran.

Study design, size, duration

This cross-sectional study performed on 25000 patients’ files admitted to the Royan institute during the period 2009- 2021.Infertile men carrying balanced chromosomal rearrangements were included as case group. Sperm parameters, DFI and common chromosomal break points were evaluated

Participants/materials, setting, methods

25000 files of patients were reviewed. 252 infertile men carrying balanced chromosomal rearrangements and 252 men with normal karyotype were included (case and control group, respectively). Sperm concentration, motility (CASA), sperm morphology (Papanicolaou Staining),DFI (SCSA) and cytogenetic analysis of peripheral blood lymphocytes (G-banding) were evaluated. Numerical chromosomal abnormalities, deletions, marker chromosomes, alcohol or drug addiction, smoking, chemotherapy and radiation, varicocele and exposure to environmental pollution were excluded. The common chromosomal breakpoints in translocations were investigated.

Main results and the role of chance

Sperm concentration, total motility and normal morphology were significantly lower in balanced chromosomal rearrangements carriers compared to control group(p < 0.05). DFI in patient was significantly higher in comparison to control group(p < 0.05). Among different kind of chromosomal rearrangement carriers’, sperm concentration and total motility were lower in Robertsonian translocation carriers comparing to the Reciprocal translocation and inversion ones. The reciprocal translocation and inversion carriers did not differ regarding to sperm concentration and total motility. Meanwhile, normal morphology was lower in the translocation compared to inversion carriers. No difference was observed in DFI among carriers of balanced chromosomal rearrangements. Among case group, inversion accounted for the largest share, followed by Reciprocal, Robertsonian translocation and insertion. Group C had the highest frequency in reciprocal translocation, inversion and insertion among the chromosomal groups. The highest balanced translocation prevalence was related to three chromosomes 9,3, and1. 9q12,1p36,3p11 were the most frequent breakpoints among them. Chromosome 9 had the largest contribution to inversions,22 to reciprocal translocations and14 to Robertsonian translocations. In the Robertsonian translocation, group D showed the highest frequency. Interestingly, patients carrying normal variations such as pericentric inversion of chromosome 9showed a significant alteration in sperm parameters, therefore normal variations showed a possible relationship to infertility.

Limitations, reasons for caution

In order to achieve stronger statistical results on DFI, a larger sample size would be more helpful.

Wider implications of the findings

The results may be useful to identify the most common breakpoints and consequently genes related to male infertility and can suggest appropriate molecular mechanism for their infertility.

Trial registration number

not applicable

Comparative evaluation of amniotic fluid as an alternative to fetal bovine serum in the maintenance of Leishmania major and Toxoplasma gondii

This study aimed to evaluate the efficacy of amniotic fluid (AF) as an alternative to fetal bovine serum (FBS) in the maintenance of Leishmania major promastigotes and Toxoplasma gondii tachyzoites. AF was collected by an obstetrician using sterile syringes during a cesarean section. The culture medium was supplemented with 5 different concentrations of FBS or AF including 2, 5, 10, 20, and 30%. These concentrations were used to maintain both mentioned parasites. L. major was maintained at temperatures 4 and 24 °C and examined once a week for 4 weeks, while T. gondii was maintained at temperatures 4, 24, and 37 °C and examined at hours 24, 48, 72, and 96. For L. major, at both 4 and 24 °C, we observed no significant difference between FBS and AF on day 7. However, on days 14, 21, and 28, the difference between FBS and AF was significant at both temperatures. For T. gondii, no significant difference was observed between FBS and AF at hour 24 and all temperatures. However, this difference was significant at hours 48, 72, and 96 and all temperatures. According to our results, although FBS had a greater efficacy than AF in the growth of L. major and the survival of T. gondii, the number of promastigotes increased over time in AF-containing medium and the number of tachyzoites reduced slowly with a mild slop. Therefore, AF can be a potential alternative to FBS.

Effects of Education Based on Health Belief Model on Dietary Behaviors of Iranian Pregnant Women

Introduction:

Mothers and children are the most vulnerable members of every society. As a result many deaths occur in these two groups, so caring for these two groups is very important. Today, it is believed that the health of an infant is related to the health of their mother. Maintaining a healthy weight before pregnancy, and optimal weight gain during pregnancy by appropriate and sufficient nutrition, are two effective measures for the prevention of low birth weight.To provide successful health interventions, it is essential to design and implement effective health education programs. Successful education also depends on the proper use of theories and models in health education. The Health Belief Model is a model that illustrates the relationship between beliefs and health, and it is based on the hypothesis that preventive health behavior consists of personal beliefs. The aim of this study was to assess the effects of training on the Health Belief Model on dietary behaviors of a sample of pregnant Iranian women.

Materials and Methods:

This study was a randomized controlled clinical trial, involving 130 pregnant women who attended two health care centers of Shahid Beheshti University of Medical Sciences. Data was collected by a structured questionnaire in three parts and seven sub-scales (including demographic characteristics, knowledge and dietary behaviors) based on the Health Belief Model.

Principles of education were based on the Health Belief Model and performed twice during two-hour sessions in the intervention group. Women in the control group received routine care and did not receive training on the above model. In order to evaluate the intervention, the previously mentioned questionnaire was administered one month after completion of the intervention, and filled by participants in both groups. Data were analyzed by SPSS software and reported with diagrams and tables.

Results:

The mean score for each variable before the intervention, except for the performance guide variable, was not significantly different between the two groups (p<0.05).

A month after the intervention, the mean scores of the knowledge, perceived severity, perceived benefits in each group, were significantly different.

These results demonstrated that there were significant differences between the two groups in terms of mean scores of knowledge, perceived severity, perceived barriers, performance guide and individual performance, and the means of these variables in the intervention group were also higher than the control group. On the other hand, after the intervention, there was no statistically significant difference found in the mean scores of perceived benefits and perceived susceptibility between the two groups (two independent samples t-test, P <0/001).

Conclusion:

Educational interventions based on health promotion patterns can be effective in enhancing awareness, better understanding of risks, reducing barriers to healthy behavior and ultimately, improving women’s health and nutritional performance during pregnancy.

DP-1: a cell cycle-regulated and phosphorylated component of transcription factor DRTF1/E2F which is functionally important for recognition by pRb and the adenovirus E4 orf 6/7 protein

The cellular transcription factor DRTF1/E2F integrates cell cycle events with the transcription apparatus through its cyclical interactions with important regulators of cellular proliferation. Two sequence-specific DNA binding proteins, DP-1 and E2F-1, are components of DRTF1/E2F which synergistically interact in a DP-1/E2F-1 heterodimer. Here, we show that DP-1 is a very frequent, possibly universal, component of DRTF1/E2F in 3T3 cells since it is present in all forms of the DNA binding activity that occur during cell cycle progression. Furthermore, the DP-1 polypeptide, which is phosphorylated, undergoes a phosphorylation-dependent mobility shift during the cell cycle suggesting that its level of phosphorylation is regulated during cell cycle progression. A C-terminal region in DP-1 can interact with pRb which, in the context of the DP-1/E2F-1 heterodimer, contributes to the efficiency of pRb binding. The DP-1/E2F-1 heterodimer specifically interacts with the adenovirus type 5 E4 orf 6/7 protein, to produce a DNA binding activity which binds co-operatively to, and transcriptionally activates through, two appropriately positioned E2F sites in a manner which resembles the regulation of DRTF1/E2F by E4 orf 6/7 during adenovirus infection. We conclude that DP-1 is a frequent and cell cycle-regulated component of DRTF1/E2F, and that in the DP-1/E2F-1 heterodimer it is functionally important for recognition by pRb and the E4 orf 6/7 protein.

Functional synergy between DP-1 and E2F-1 in the cell cycle-regulating transcription factor DRTF1/E2F

It is widely believed that the cellular transcription factor DRTF1/E2F integrates cell cycle events with the transcription apparatus because during cell cycle progression in mammalian cells it interacts with molecules that are important regulators of cellular proliferation, such as the retinoblastoma tumour suppressor gene product (pRb), p107, cyclins and cyclin-dependent kinases. Thus, pRb, which negatively regulates early cell cycle progression and is frequently mutated in tumour cells, and the Rb-related protein p107, bind to and repress the transcriptional activity of DRTF1/E2F. Viral oncoproteins, such as adenovirus E1a and SV40 large T antigen, overcome such repression by sequestering pRb and p107 and in so doing are likely to activate genes regulated by DRTF1/E2F, such as cdc2, c-myc and DHFR. Two sequence-specific DNA binding proteins, E2F-1 and DP-1, which bind to the E2F site, contain a small region of similarity. The functional relationship between them has, however, been unclear. We report here that DP-1 and E2F-1 exist in a DNA binding complex in vivo and that they bind efficiently and preferentially as a heterodimer to the E2F site. Moreover, studies in yeast and Drosophila cells indicate that DP-1 and E2F-1 interact synergistically in E2F site-dependent transcriptional activation.

Transcriptional repression by the Rb-related protein p107

The transcription factor DRTF1/E2F is believed to play an important role in regulating cellular proliferation because it undergoes a series of periodic interactions with proteins that are known to be important regulators of the cell cycle, including the retinoblastoma gene product (pRb) and cyclin A. Furthermore, certain viral oncogene products, such as adenovirus E1a, disrupt these DRTF1/E2F complexes by sequestering the associated proteins. p107, a protein that is structurally related to pRb, also binds to DRTF1/E2F, and in this study we investigate the functional consequences of this interaction. We show that p107 can repress E2F binding site-dependent transcription and that the adenovirus E1a protein overcomes p107-mediated transcriptional repression. Two distinct but related proteins, pRb and p107, can therefore repress transcription driven by DRTF1/E2F, whereas the E1a protein overrides the repression. We also demonstrate that the transcription repressing properties of p107 and pRb are influenced by the cell type and by differentiation, because neither protein affects transcription in F9 embryonal carcinoma (EC) cells but both do so efficiently in differentiated derivatives. In this respect, the repressing activities of pRb and p107 inversely correlate with the presence of the cellular E1a-like activity previously documented in F9 EC cells. These data suggest that p107 and pRb exert their biological activities in some but not all cell types.

Isolation and characterization of Escherichia coli mutants affected in aerobic respiration: the cloning and nucleotide sequence of ubiG. Identification of an S-adenosylmethionine-binding motif in protein, RNA, and small-molecule methyltransferases

We report the isolation and characterization of a mutant of Escherichia coli unable to grow aerobically on non-fermentable substrates, except for very slow growth on glycerol. The mutant contains cytochrome oxidases o and d, and grows anaerobically with alternative electron acceptors. Oxygen consumption rates of cell-free extracts were low relative to activities in an isogenic control strain, but were restored in vitro by adding ubiquinone-1 to cell-free extracts. Transformation with a cloned 2.8 kb ClaI-EcoRV fragment of chromosomal DNA restored the ability of this mutant (AN2571) to grow on succinate and also restored cellular quinone levels in this strain. The plasmid also complemented a previously isolated ubiG mutant (AN151) for aerobic growth on succinate. The nucleotide sequence revealed a 0.7 kb portion of gyrA. Unidirectional nested deletions from this fragment and complementation analysis identified an open reading frame encoding a protein with a predicted molecular mass of 26.5 kDa. This gene (ubiG) encodes the enzyme 2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone methyltransferase, which catalyses the terminal step in the biosynthesis of ubiquinone. The open reading frame is preceded by a putative Shine-Dalgarno sequence and followed by three palindromic unit sequences. Comparison of the inferred amino acid sequence of UbiG with the sequence of other S-adenosylmethionine (AdoMet)-dependent methyltransferases reveals a highly conserved AdoMet-binding region. The cloned 2.8 kb fragment also contains a sequence encoding the C-terminus of a protein with 42-44% identity to fungal acetyl-CoA synthetases.

Adenovirus E1a prevents the retinoblastoma gene product from repressing the activity of a cellular transcription factor

The retinoblastoma (Rb) gene product forms a complex with the cellular transcription factor DRTF1, a property assumed to be important for mediating negative growth control because certain viral oncogenes, such as adenovirus E1a, prevent this interaction and mutant Rb alleles, which have lost the capacity to regulate growth, encode proteins that fail to associate with DRTF1. In this study, we show that the wild-type Rb protein can specifically repress transcription from promoters driven by DRTF1 whereas a naturally occurring mutant Rb protein cannot. Furthermore, Rb-mediated transcriptional repression can be overridden by adenovirus E1a; this requires regions in E1a necessary for cellular transformation. The Rb protein therefore acts in trans to repress the transcriptional activity of DRTF1 whereas adenovirus E1a prevents this interaction and thus maintains DRTF1 in a constitutively active state. The Rb protein and adenovirus E1a therefore have opposite effects on the activity of a common molecular target. Transcriptional repression mediated by the Rb protein and inactivation of repression by the E1a protein are likely to play an important role in mediating their biological effects.

Cyclin A recruits p33cdk2 to the cellular transcription factor DRTF1

Cyclins are regulatory molecules that undergo periodic accumulation and destruction during each cell cycle. By activating p34cdc2 and related kinase subunits they control important events required for normal cell cycle progression. Cyclin A, for example, regulates at least two distinct kinase subunits, the mitotic kinase subunit p34cdc2 and related subunit p33cdk2, and is widely believed to be necessary for progression through S phase. However, cyclin A also forms a stable complex with the cellular transcription factor DRTF1 and thus may perform other functions during S phase. DRTF1, in addition, associates with the tumour suppressor retinoblastoma (Rb) gene product and the Rb-related protein p107. We now show, using biologically active fusion proteins, that cyclin A can direct the binding of the cdc2-like kinase subunit, p33cdk2, to complexed DRTF1, containing either Rb or p107, as well as activate its histone H1 kinase activity. Cyclin A cannot, however, direct p34cdc2 to the DRTF1 complex and we present evidence suggesting that the stability of the cyclin A-p33cdk2 complex is influenced by DRTF1 or an associated protein. Cyclin A, therefore, serves as an activating and targeting subunit of p33cdk2. The ability of cyclin A to activate and recruit p33cdk2 to DRTF1 may play an important role in regulating cell cycle progression and moreover defines a mechanism for coupling cell-cycle events to transcriptional initiation.

Benzene dioxygenase in Pseudomonas putida. Subunit composition and immuno-cross-reactivity with other aromatic dioxygenases

The terminal oxygenase component of benzene dioxygenase from Pseudomonas putida strain ML2 was shown to contain two subunits, of Mr 54,500 and 23,500, by SDS/polyacrylamide-gel electrophoresis. The native Mr of the terminal oxygenase was estimated to be 168,000 +/- 4000. Polyclonal antibodies raised against each of the subunits cross-reacted with two polypeptides in cell-free extracts from toluene-grown Pseudomonas putida strain N.C.I.B. 11767. The Mr values of these polypeptides were similar to those reported for the subunits from the terminal dioxygenase component of toluene dioxygenase. These polypeptides were present only when this strain was grown on toluene. No cross-reactivity was observed with subunits of the naphthalene dioxygenase or benzoate dioxygenase systems.