Effects of tetracycline on entomopathogenic nematodes and their bacterial symbionts

Among the new contaminants relevant for environment, one of the most significant roles is played by pharmaceuticals like antibiotic products for either human or veterinary use. Their presence could cause serious damage to bacteria and microfauna, like nematodes. Within the widely investigated nematodes, very little is known about the interaction between antibiotics and entomopathogenic nematodes (EPN). EPNs have been used for biological control of crops, due to their ability to penetrate arthropod pests and kill their hosts thanks to a complex symbiotic mechanism with specific gram-negative bacteria. Tetracycline is an antibiotic used in human and veterinary medicine, both for therapeutic purposes and for the growth of livestock. Since its action against gram-negative bacteria is documented, we verified in this study the survival, growth and pathogenicity of two species of EPNs, Steinernema vulcanicum and S. feltiae. All tests were performed with tetracycline in 1% ethanol solution and up to 300 mg/L. Apparently, this incubation did not harm the vitality of EPNs. Both S. vulcanicum as S. feltiae recovered their vitality and entomopathogenic ability after 48 h. Moreover, the latter EPN species did not grow nor reproduce in the hemolymph of the Greater Wax Moth, Galleria mellonella, and their endosymbionts did not grow on MacConkey Agar. Our results suggest that the first EPN species has always retained all its abilities and that endosymbionts have acquired resistance to tetracycline, while experiments with the second EPN species provided some contrasting results in time that will require further investigations.

Observation of π^{-}K^{+} and π^{+}K^{-} Atoms

The observation of hydrogenlike πK atoms, consisting of π^{-}K^{+} or π^{+}K^{-} mesons, is presented. The atoms are produced by 24  GeV/c protons from the CERN PS accelerator, interacting with platinum or nickel foil targets. The breakup (ionization) of πK atoms in the same targets yields characteristic πK pairs, called "atomic pairs," with small relative momenta Q in the pair center-of-mass system. The upgraded DIRAC experiment observed 349±62 such atomic πK pairs, corresponding to a signal of 5.6 standard deviations. This is the first statistically significant observation of the strange dimesonic πK atom.

Expression of SPANX proteins in normal prostatic tissue and in prostate cancer

The sperm protein associated with the nucleus in the X chromosome (SPANX) gene family encodes for proteins that are not only expressed in germ cells, but also in a number of tumors. In addition, SPANX genes map in an interval of the X chromosome (namely, Xq27), which has been found to be associated with familial prostate cancer by linkage analysis. The aim of this study was therefore to evaluate SPANX protein expression in normal prostate tissues and in prostate carcinoma. For this purpose, formalin-fixed and paraffin-embedded sections obtained from 15 normal (at autopsy) donors and 12 men with prostate cancer were analyzed by immunohistochemistry. About 40% of both normal and tumor prostate samples resulted SPANX positive. Signals were exclusively within the nucleus in normal prostate cells, whereas both nuclear and cytoplasmic positivity was observed in tumor cells. In conclusion, these findings showed that SPANX genes are expressed in both normal and tumor prostate gland, but the latter showed a peculiar cytoplasmic staining positivity. This suggests a possible association between SPANX over expression and prostate cancer development. Additional studies are needed to corroborate this hypothesis.

Spontaneous transmission from a father to his son of a Y chromosome microdeletion involving the deleted in azoospermia (DAZ) gene

Microdeletions of the so-called azoospermia factor (AZF) locus of the Y chromosome long arm (Yq) have been recognized as an etiological factor of severe oligozoospermia or azoospermia. Because of this, patients affected are generally infertile unless assisted reproductive techniques are used. We report the case of an oligozoospermic patient (proband) who inherited an extensive Yq microdeletion from his father through a spontaneous pregnancy. Leukocyte DNA was extracted using a commercially available kit. A total of 22 pairs of sequence-tagged site (STSs) based primers, spanning the entire AZF region, were used for the screening. Both the proband and his father carried a Yq microdeletion of the most distal AZF subregion (AZFc) where the deleted in azoospermia (DAZ) gene is located. The proband's father was a sixty-nine-yr-old man who had 3 other children, 2 females and 1 male. This case adds further evidence that the deletion of the DAZ gene is associated with different phenotypic expressions, including normal fertility.

Two new point mutations at A2062 associated with resistance to 16-membered macrolide antibiotics in mutant strains of Mycoplasma hominis

We describe two mutants of Mycoplasma hominis PG-21 which show resistance to 16-membered macrolides but susceptibility to lincosamides, obtained by in vitro exposure to increasing doses of josamycin. The 23S rRNA gene showed that each had a mutation (A2062G and A2062T) corresponding to nucleotide 2062 in Escherichia coli, which was associated with the acquired phenotype.

rrn operons in Haemophilus parainfluenzae and mosaicism of conserved and species-specific sequences in the 16S-23S rDNA long spacer

The mosaic organisation of short-sequence boxes was analysed in the cloned and sequenced long ribosomal spacer (547 bp) of Haemophilus parainfluenzae GR. Comparison and alignment of both the long and the short spacer were performed in H. parainfluenzae and H. influenzae Rd. The long spacer contained two tRNA genes (tRNA(Ala) and tRNA(Ile)) which are highly homologous to the corresponding genes found in the spacers of other species, such as Haemophilus spp., Actinobacillus spp., and Plesiomonas shigelloides. At the 3' end of tRNA(Ala) a putative ribosomal spacer loop was found, showing a strong secondary structure. Pulsed field gel electrophoresis (PFGE) analysis after restriction of the genome of H. parainfluenzae GR with I-Ceu I and subsequent polymerase chain reaction (PCR) analysis of PFGE-separated DNA fragments demonstrated that the H. parainfluenzae genome contained six operons and that the long spacer was present in three copies of them. Two short DNA segments were identified as being species-specific, allowing us to design PCR primers which were useful in the molecular identification of H. parainfluenzae isolates.

Aneuploidy rate in spermatozoa of selected men with abnormal semen parameters

A large proportion of patients with oligoasthenoteratozoospermia (OAT) have an abnormal karyotype and hence they produce aneuploid gametes. However, a normal karyotype does not exclude the chance of having germ cell aneuploidy, since an altered intra-testicular environment not only damages spermatogenesis, but may also disrupt the mechanisms controlling chromosomal segregation during meiosis. Therefore, this study was undertaken to evaluate the rate of aneuploidy in the spermatozoa of selected patients with abnormal sperm parameters. For this purpose, sperm aneuploidy rate for chromosomes 8, 12, 18, X and Y was evaluated by multicolour fluorescence in-situ hybridization (FISH) in nine patients with teratozoospermia alone and 19 OAT patients of presumably testicular origin. Thirteen normozoospermic healthy men served as controls. Patients with teratozoospermia or OAT had significantly greater disomy and diploidy rates compared with controls, whereas the rate of nullisomy was similar. XY disomy was very low in all groups, suggesting that chromosomal non-disjunction occurs mainly during the second meiotic division. Autosome 12 disomy rate was low in both patients and controls. There was a marked variability of total sperm aneuploidy rate in both groups of patients. Sperm aneuploidy rate was negatively correlated with sperm concentration and particularly with the percentage of normal forms. In conclusion, patients with teratozoospermia or OAT have an increased rate of sperm aneuploidy. This increase is similar in both groups, suggesting that teratozoospermia may be the critical sperm parameter associated with aneuploidy.

Reverse transcription polymerase chain reaction method for the detection of glycopeptide resistance in enterococci

In this work we have developed reverse transcription polymerase chain reaction (RT-PCR) methods for detecting specific mRNA from enterococci, particularly vanA and vanB genes, responsible for glycopeptide resistance in this genus. mRNA from the two genes was detected immediately after RNA extraction of a midlog phase culture, determined by growth rate analysis. Because of the short half-life associated with many bacterial RNA species (1.5-2 min), time is an important factor in obtaining RNA of good yield and high purity. Our results showed that: (i) the transcription of mRNA related to vanA ligase in enterococci showing Van A phenotype happens only after induction with both vancomycin and teicoplanin; (ii) the transcription of mRNA related to vanB ligase happens only in the presence of vancomycin and (iii) there was no transcription of mRNA in the two strains positive to vanA gene after PCR experiments. RT-PCR methodology can have numerous applications in microbiology for studying gene expression in isolated bacteria and also in nonculturable cells in environmental samples, for studies of mechanisms and/or as an indicator of viability in bacterial communities.

Cloning and sequencing of a 16S/23S ribosomal spacer from Haemophilus parainfluenzae reveals an invariant, mosaic-like organisation of sequence blocks

A 16S/23S ribosomal spacer from a Haemophilus parainfluenzae rrn locus was cloned and sequenced. Analysis of PCR-amplified genomic fragments showed that this region is strongly conserved among unrelated isolates; computer analysis of database homologies showed that the spacer consists of sequence blocks, arranged in a mosaic-like structure, with strong homologies with analogous blocks present in the spacer regions of Haemophilus influenzae, Haemophilus ducreyi and Actinobacillus spp. It also contains a tRNA(Glu) gene, which is highly homologous to tRNA(Glu) genes found in spacers of other species. These data strongly support the hypothesis that recombination events are involved in the organisation of the sequence of the spacer, as a result of horizontal gene transfer.

Molecular epidemiology and phylogenetic analysis of Haemophilus parainfluenzae from chronic obstructive pulmonary disease exacerbations

This study was undertaken to characterize serial Haemophilus parainfluenzae strains from epidemiologically unrelated chronic obstructive pulmonary disease (COPD) patients and from healthy carriers. A comprehensive approach was used including different phenotypical and molecular typing methods: biotyping, antibiotyping, conventional ribotyping, pulsed field gel electrophoresis (PFGE) assay, and PCR-ribotyping. Conventional ribotyping and PFGE analysis were confirmed as excellent procedures to differentiate isolates of the same species and biotype. Conversely, in our study, PCR-ribotyping proved to be suitable for taxonomic purposes, unambiguously identifying H. parainfluenzae from H. influenzae but not discriminating strains at the intraspecific level for epidemiological typing. Phylogenetic analysis of restriction fragment length polymorphism (RFLP) data of sequences related to the rrn operon demonstrated that H. parainfluenzae strains associated to COPD are spread among many diverging lineages.

Human NRD convertase: a highly conserved metalloendopeptidase expressed at specific sites during development and in adult tissues

We report the cloning of the human homologue of the rat metalloprotease N-arginine dibasic convertase (NRD convertase). This endopeptidase is responsible for the processing, at the Arg-Lys dibasic site on the N-terminal side of the arginine residue, of propeptides and proproteins. Comparisons of the human and rat full-length cDNAs show similarity and identity of 94 and 91%, respectively. In humans NRD convertase is predominantly expressed in heart, skeletal muscle, and testis. We have also studied the expression of this gene in mouse at various developmental stages and found that the neural tissue is the almost exclusive site of expression in early development (between E 10.5 and E 16.5). To gain information about the possibility that defects in this gene are linked to inherited neuromuscular disorders, we determined the chromosomal location of the human NRD convertase gene by FISH analysis, showing that the gene resides at 1p32.2.

[Repetitive movement of the upper limbs: results of exposure evaluation and clinical investigation in cash register operators in supermarkets]

In order to evaluate the prevalence of joint and periarticular disorders of the upper limbs attributable to repetitive movements (WMSDs), 100 female supermarket cashiers were examined. Their average age was 29.5 years (SD = 6.3), and their average length of service was 3.9 years (SD = 1.9). Only 26% of the women were anamnestically negative for WMSDs, while 74% had one or more disorders due to repetitive trauma of the upper limbs, although a definite diagnosis could be made in only 33 cases. The majority of the disorders affected the right side and the localisation was primarily in the shoulder and wrist. The risk factor analysis on the one hand confirmed that high-frequency repetitive movements of the wrist and hand, associated with inadequate recovery times, do play a role in determining the onset of upper limb and carpal tunnel syndrome. On the other hand, the study also revealed a definite need to review the way the work is organised, so that each shift at the cash register includes suitable functional recovery periods.

[Repetitive movement of the upper limbs: results of exposure evaluation and clinical investigation during jar packaging of preserved vegetables]

In order to assess the prevalence of work-related musculo-skeletal disorders of the upper limbs, a total population of 29 female workers in an industrial vegetable preserving plant were examined. The average age of the workers was 41.3 years (SD = 9.2), and their average length of service was 16.7 years (SD = 7.2). Only 20% of the workers were anamnestically negative, whilst 80% had one or more disorders attributable to repetitive trauma of the upper limbs. The disorders showed no prevalence for the right side, a finding in line with the risk analysis which indicated that both limbs were equally used. The results of the risk analysis and clinical assessment confirm that high-frequency actions, combined with improper posture and a shortage of suitable recovery times, play a causal role in determining the onset of the disorders studied.

Cloning a fragment from the telomere of the long arm of human chromosome 9 in a YAC vector

The construction of a yeast artificial chromosome containing a human DNA insert is reported. This molecule of about 200 kb behaves as a native yeast chromosome since it has a very high mitotic stability and is present in the yeast transformant clone at a copy number similar to that of the resident chromosomes. Hybridization with the TTAGGG sequence demonstrates that this chromosome contains human telomeric sequences. In situ hybridization of the biotin-labelled artificial chromosome to metaphase human chromosomes shows that the insert occupies a telomeric position on the long arm of chromosome 9. Since the fragment was cloned as an EcoRI insert and not as a telomere, it is situated medially to the telomeric sequences and harbours telomere-associated sequences, that have been shown to contain the TTAGGG sequence. The fragment represents the end of the genetic map of chromosome 9 and thus can be used to characterize the sequence and the structure of the chromosomal region that runs from the end of the chromosome to the first gene.

Resistance of HSV-1 growth to aphidicolin in two aphidicolin resistant cell lines

The growth of herpes simplex virus type 1 (HSV-1) was examined in two cell lines resistant to aphidicolin by inhibition of infectious progeny production in the presence of the drug. The results reported show that the virus yield, which was severely inhibited by the drug in sensitive cells, was only slightly inhibited in the resistant cell lines. This suggests that the metabolic alteration known to confer resistance to the cell line (that is the altered deoxyribonucleoside triphosphate pool) may also allow viral growth to proceed in the presence of aphidicolin, and that therefore HSV replication at least partially depends upon the host replicative apparatus.