Could the egg itself be the source of the oviposition deterrent marker in the ectoparasitoid Dinarmus basalis?

Females of Dinarmus basalis, a solitary ectoparasitoid, strongly avoid superparasitising hosts bearing eggs which are 20 or more hours old. Our objective was to determine the mechanism by which the factors inducing host discrimination and such an oviposition deterring effect act, and the origin of the deterrent. This study showed that the information is carried by the parasitised host. It is acquired by a transfer of molecules from the wasp egg onto the host and it requires contact between egg and host for at least 4 h. The factors transferred do not, as commonly reported in other species, come from the female's genital apparatus but from the live egg itself. Consequently, the D. basalis egg directly participates in the success of parasitism by releasing factors which elicit the oviposition host deterring effect. The originality and the ecological importance of these results are discussed.     

Could an endo-lysosomal ion channel be the Achilles heel of SARS-CoV2?

The ongoing SARS-CoV2 outbreak has developed into a global pandemic. Despite previous outbreaks of SARS-CoV and the related MERS-CoV in recent years, neither a vaccine nor any other medication for an effective treatment are currently available. Endo-lysosomal two-pore cation channels have now emerged as potential novel targets for SARS-CoV treatment.     

Redox control of gene expression and the function of chloroplast genomes — an hypothesis

Two-component regulatory systems that respond to changes in redox potential have recently been discovered in bacteria. Redox sensors are defined as electron carriers which initiate control of gene expression upon oxidation or reduction. Redox response regulators are defined as DNA-binding proteins which modify gene expression as a result of the action of redox sensors. Redox sensors and redox response regulators may comprise a mechanism for feedback control of redox potential in photosynthetic electron transport chains, thereby protecting plants, algae and photosynthetic bacteria from damage caused by electrochemistry operating on inappropriate electron donors and acceptors. Chloroplast redox sensors and redox response regulators, themselves encoded in the nucleus, may place chloroplast gene expression under redox regulatory control. This may account for the persistence, in evolution, of chloroplast genomes, and for the constancy of the sub-set of chloroplast proteins encoded and synthesised in situ. These and other predictions are discussed.     

Could antifungal lock be useful in the management of candidiasis linked with catheters?

Fungal biofilms associated with inserted medical devices such as catheters, represent a major risk factor for candidemia. In addition, these biofilm yeasts show a decreased susceptibility to antifungal agents. Recently, a new therapeutic approach has emerged, the "lock therapy", based on the use of high concentrations of antimicrobials, instilled into the lumen of the catheter and left in place for 8 to 12 h. In?vitro or in?vivo studies have evaluated the interest of antifungal locks using amphotericin B, an azole or echinocandins. The promising results will permit us to discuss the relevance of this technique.     

The roles and expression of HOXA/Hoxa10 gene: A prospective marker of mammalian female fertility?

This review addresses the influence of homebox A10/a10 (HOXA/Hoxa10) gene on reproductive tract anatomy and functional fertility in mammalian species, and discusses major endocrine and environmental regulators of HOXA/Hoxa10 expression. Female reproductive efficiency or success is a function of several factors including the ovulation and fertilization rate, and uterine receptivity. A family of HOX/Hox genes establishes the segmental identity of the reproductive tract during embryogenesis and retains its physiological plasticity in sexually mature animals and humans. In particular, the HOXA/Hoxa10 gene is an intrinsic component of implantation, decidualization, and immunomodulation in the adult uterus. It was, therefore, suggested that knowledge of HOXA/Hoxa10 regulation might be essential in navigating molecular mechanisms with the aim of enhancing female reproductive potential. However, a recent study in pigs revealed a lack of associations between endometrial HOXA10 expression and reproductive tract morphology, and very poor correlations with sows’ fertility metrics. Retinoic acid mainly regulates 3’ HOX/Hox paralogs but may also modify the expression of downstream HOX/Hox genes, including HOXA/Hoxa10. Sex steroids directly regulate HOXA/Hoxa10 expression. The vitamin D receptor pathway modulates HOXA/Hoxa10 expression in the adult reproductive tract. Lastly, endocrine disruptors such as diethylstilbestrol, methoxychlor, bisphenol A, and isoflavones were shown to alter HOXA/Hoxa10 expression, thus affecting reproductive competence of the female.     

Increased levels of albumin in bronchial washing fluid of patients with bronchial carcinoma. Could albumin be considered as a tumor marker?

BACKGROUND: The aim of this study was to evaluate the significance of albumin in bronchial washing fluid (BWF) and its relationship to three tumor markers (CEA, CA 19-9 and NSE). METHODS: Serum and BWF samples were collected in a group of 60 patients. Albumin and tumor markers in the BWF and serum of three groups: a control group (CG), a chronic bronchitis group (CBG) and a lung cancer group (CaG), were analyzed in a prospective cross-sectional study. The diagnostic yields of the tests in each environment (serum and BWF) were evaluated by using as cutoff points the values of the corresponding 90th percentile of CG and CBG taken together. RESULTS: A significant difference in albumin level (p < 0.001) was noted in the BWF of patients with cancer compared with the other two groups. In addition, a significant difference in CEA level (p < 0.001) was observed in the serum of cancer patients compared with the other two groups. The cutoff values for CEA in serum and albumin in BWF were 2.20 ng/mL and 2.00 g/dL, respectively. The areas under the corresponding ROC curves were 93% and 97%. Combination of CEA-serum and albumin-BWF by logistic regression analysis increased their diagnostic value. CONCLUSION: Measurement of albumin levels in BWF could be a useful additional diagnostic tool to differentiate malignant from non-malignant lung diseases. Moreover, the combined measurement of CEA in serum and albumin in BWF could be of aid in the follow-up of lung cancer patients.     

The isolation of genomic recombinants for the human apolipoprotein B gene and the mapping of three common DNA polymorphisms of the gene —a useful marker for human chromosome 2

Summary We have used four independently isolated cDNA probes for human apolipoprotein B (apo B), to isolate overlapping genomic recombinants for the 3 portion of the apo B gene. The cDNA clones and a unique fragment from the genomic recombinant have been used to identify the human apo B gene in DNA from a series of roden x human somatic cell hybrids. Our results provide evidence for the assignment of this gene to the short arm of human chromosome 2 (p23-pter). We have used the cDNA probes to identify three common DNA polymorphisms. The first, detected with the restriction enzyme XbaI and our probe pAB4, has a rare allele frequency of 0.48. The other two polymorphisms are detected with the probe pAB3. The enzyme MspI detects at least three alleles, with frequencies of 0.67, 0.16 and 0.15, while that detected with the enzyme EcoRI has a rare allele frequency of 0.12. The relative position of these polymorphisms has been mapped using the genomic recombinants.Investigation of a small number of haplotypes indicares that there is linkage equilibrium between the polymorphisms, which have a total polymorphism information content (PIC) value of more than 0.8. These polymorphisms will provide useful markers for genetic studies on chromosome 2 and for the analysis of the involvement of variants of the apo B gene in the development of hyperlipidaemia.     

The case of an infertile male with an uncommon reciprocal X-autosomal translocation: how does this affect male fertility?

Infertility is defined as the inability to conceive after one year of regular unprotected intercourse. Constitutional numerical and/or structural chromosomal aberrations like sex-chromosome aberrations are one of the possible factors involved in fertility problems. Reciprocal translocations between an X-chromosome and an autosome are rarely seen in men. Male carriers of an X-autosome translocation are invariably sterile, regardless of the position of the breakpoint in the X-chromosome. Breakpoints in autosomal chromosomes could also be involved in male infertility. In this paper, we describe a 31-year-old male with azoospermia. GTG banding with high resolution multicolor-banding (MCB) techniques revealed a karyotype 46,Y,t(X;1)(p22.3;q25), and we discuss how the breakpoint of this translocation could affect male infertility. As a conclusion, cytogenetic evaluation of infertile subjects with azoospermia should be considered in the first place before in vitro fertilisation procedures are planned.     

The fermentation of xylose —an analysis of the expression of Bacillus and Actinoplanes xylose isomerase genes in yeast

Summary The genes encoding xylose isomerase from Bacillus subtilis and Actinoplanes missouriensis have been isolated by complementation of a xylose isomerase defective Escherichia coli mutant. The xylose isomerase gene from A. missouriensis could be expressed in E. coli under the control of its own promoter, whereas the cloned Bacillus gene was expressed in E. coli only after the spontaneous integration of the E. coli IS5 element. After fusion of the Bacillus gene to the yeast PDC1 promoter, transformants of Saccharomyces cerevisiae contained the xylose isomerase protein. Approx. 5% of the total cellular protein of transformants consisted of xylose isomerase that was found to be at least partly insoluble. Neither the insoluble protein nor Triton X-114 solubilized isomerase was catalytically active. To investigate whether the xylose isomerase of A. missouriensis can be expressed in S. cerevisiae the coding region was fused to the yeast GAL1 promoter. Analysis of total RNA from yeast transformants containing this construction showed a xylose isomerase specific mRNA.Dedicated to Professor Karl Esser on the occasion of his 60th birthday     

Could the expression of CD86 and FcγRIIB on B cells be functionally related and involved in driving rheumatoid arthritis?

Aberrant immune responses play a pivotal role in the processes that cause inflammation and joint damage in patients with rheumatoid arthritis (RA). Polyclonal B cell activation and the production of autoantibodies are immunological hallmarks of the disease. However, controversy surrounds the pathogenicity of autoantibodies, mainly because not all patients are seropositive (10% of RA patients are seronegative), suggesting that they could be markers rather than makers of disease. Catalán and collaborators report that patients with RA display reduced expression of FcγRIIB on memory B cells and plasma cells, which inversely correlates with autoantibody levels. Considering that FcγRIIB stimulation down-regulates antibody production, this work strengthens the link between autoantibodies and pathogenicity.     

The 5‘—flanking cis—acting elements of the human ε—globin gene associates with the nuclear matrix and binds to the nuclear matrix proteins

The nuclear matrix attachment regions(MARs) and the binding nuclear matrix proteins in the 5‘-flanking cisacting elements of the human ε-globin gene have been examined.Using in vitro DNA-matrix binding assay,it has been shown that the positive stage-specific regulatory element (ε-PREII,-446bp- -419bp) upstream of this gene could specifically associate with the nuclear matrix from K562 cells,indicating that ε-PREII may be an erythroidspecific facultative MAR.In gel mobility shift assay and Southwestern blotting assay,an erythroid-specific nuclear matrix protein (ε-NMPk) in K562 cells has been revealed to bind to this positive regulatory element (ε-PREII).Furthermore,we demonstrated that the silencer (-392bp- -177bp) upstream of the human ε-globin gene could associate with the nuclear matrices from K562,HEL and Raji cells.In addition,the nuclear matrix proteins prepared from these three cell lines could also bind to this silencer,suggesting that this silencer element might be a constitutive nuclear matrix attachment region(constitutive MAR).Our results demonstrated that the nuclear matrix and nuclear matrix proteins might play an important role in the regulation of the human ε-globin gene expression.     

Sequencing of genes within the vir regulon of Streptococcus pyogenes type M15 — an opacity factor-positive serotype with low opacity factor expression

Major virulence determinants of group A streptococci, such as M-protein, immunoglobulin Fc-receptors (FcRA, EmmL) and C5a peptidase, appear to be genetically co-regulated, their genes being located within a vir regulon. We studied the organization of these genes in a group A, type M15 strain of Streptococcus pyogenes, previously defined as OF^?, by hybridization analysis of chromosomal DNA and of an S. pyogenes gene library in Escherichia coli, and by gene sequencing. Within the vir regulon, in addition to the virR and scpA genes, three so-called emm-related genes were found: fcrA, emmL and enn. Whereas IgG Fc-binding proteins were encoded by fcrA and emmL, the product of enn was not identified. The presence of three emm-related genes in this region is reminescent of vir regulon organization in OF⁺ rather than OF^? strains as earlier defined by others. Furthermore, analysis of the deduced product of the emmL gene showed deletions and amino acid substitutions within the PGTS-rich domain and membrane anchor, which thus resembles corresponding products of OF⁺ rather than OF^? strains. In view of these findings, the opacity factor (OF) activity of the strain was tested using growth supernatant, with negative outcome. However, a concentrated SDS cell extract revealed definite OF activity. One of two other type M15 reference strains also showed definite OF activity in SDS extracts. We therefore propose that type M15 strains belong to the OF⁺ category but often show low levels of expression of OF.