The molecular chaperone Hsp90α is required for meiotic progression of spermatocytes beyond pachytene in the mouse

The molecular chaperone Hsp90 has been found to be essential for viability in all tested eukaryotes, from the budding yeast to Drosophila. In mammals, two genes encode the two highly similar and functionally largely redundant isoforms Hsp90α and Hsp90β. Although they are co-expressed in most if not all cells, their relative levels vary between tissues and during development. Since mouse embryos lacking Hsp90β die at implantation, and despite the fact that Hsp90 inhibitors being tested as anti-cancer agents are relatively well tolerated, the organismic functions of Hsp90 in mammals remain largely unknown. We have generated mouse lines carrying gene trap insertions in the Hsp90α gene to investigate the global functions of this isoform. Surprisingly, mice without Hsp90α are apparently normal, with one major exception. Mutant male mice, whose Hsp90β levels are unchanged, are sterile because of a complete failure to produce sperm. While the development of the male reproductive system appears to be normal, spermatogenesis arrests specifically at the pachytene stage of meiosis I. Over time, the number of spermatocytes and the levels of the meiotic regulators and Hsp90 interactors Hsp70-2, NASP and Cdc2 are reduced. We speculate that Hsp90α may be required to maintain and to activate these regulators and/or to disassemble the synaptonemal complex that holds homologous chromosomes together. The link between fertility and Hsp90 is further supported by our finding that an Hsp90 inhibitor that can cross the blood-testis barrier can partially phenocopy the genetic defects.     

Straight and branched (ω-1)-hydroxylated very long chain fatty acids are components of Bradyrhizobium lipid A

Lipopolysaccharides of seven Bradyrhizobium strains and three whole-cell fatty acid preparations from bacteria isolated from nodules of Sarothamnus scoparius (common broom) were studied for the presence of very long chain (ω-1)-hydroxy fatty acids. Several such fatty acids were identified. Among them, straight-chain as well as mono- and dimethyl branched acids with chains in the range from 26 to 34 carbon atoms were found. Pyrrolidides and 4,4-dimethyloxazoline derivatives were used to determine the branching position. Carbons at the (ω-10) and/or (ω-11) positions in alkyl chains were points of attachment of methyl groups. These data complete the structure of bradyrhizobial lipid A with important details. The obtained results can be applied in the chemotaxonomy of Bradyrhizobium.     

Isoforms of the nonclassical class I MHC antigen H2-Q5 are enriched in brain and encode Qdm peptide

Although the human nonclassical class Ib major histocompatibility complex (Mhc) locus, HLA-G, is known to act as an immune suppressor in immune-privileged sites, little is currently known regarding participation of the rodent class Ib Mhc in similar pathways. Here, we investigated the expression properties of the mouse nonclassical Mhc H2-Q5 ^k gene, previously detected in tumors and tissues associated with pregnancy. We find that H2-Q5 ^k is alternatively spliced into multiple novel isoforms in a wide panel of C3H tissues. Unlike other known class I MHC, it is most highly transcribed in the brain, where the classical class Ia Mhc products are scarce. The truncated isoforms are selectively enriched in sites of immune privilege and are translated into cell surface proteins in neural crest-derived transfected cells. Furthermore, we present data supporting a model whereby Q5^k isoforms serve an immune-protective role by donating their Qdm leader peptide to Qa-1, in a pathway homologous to the HLA-G leader fragment binding HLA-E and inhibiting CD94/NKG2A-positive cytotoxic cells. In addition, we report a previously unknown homolog of H2-Q5 ^k in the C57BL/6 mouse, which encodes Qdm, but is transcribed solely into noncanonical isoforms. Collectively, these studies demonstrate that H2-Q5 ^k , and its homologous class I-like H2 ^b gene may play tissue-specific roles in regulating immune surveillance.     

Terminal monosaccharide expression on amniotic glycoproteins as biomarkers of fetus maturity

Glycotypes, particularly those that terminate with sialic acid and fucose are known to play a fundamental role in human development, during implantation, growth and differentiation of fetal tissues. The present review describes changes in the exposition of terminal sialic acid and fucose isoforms in the amniotic fluid glycoconjugates, α1-acid glycoprotein and fibronectin during critical stages of pregnancy, i.e. second and third trimester, perinatal period, delivery and post-date pregnancy. The distinct amniotic glycoforms are suggested to be implicated in regulatory processes to ensure homoeostasis during pregnancy and to protect the fetus. These may have the potential of becoming additional laboratory makers in obstetrics to monitor pregnancy.     

Gynecomastia - a difficult diagnostic problem

Gynecomastia is a benign, abnormal, growth of the male breast gland which can occur unilaterally or bilaterally, resulting from a proliferation of glandular, fibrous and adipose tissue. Gynecomastia is characterised by the presence of soft, 2-4 cm in diameter, usually discusshaped enlargement of tissues under the nipple. It is estimated that this pathology occurs in 32-65% of men over the age of 17. Gynecomastia is a psychosocial problem and may lead to a perceived lowering of quality of life. The main cause of gynecomastia is a loss of equilibrium between oestrogens and androgens. Increased sensitivity for oestrogens of the breast gland, or local factors (e.g. an excessive synthesis of oestrogens in breast tissues or changes in oestrogen and androgen receptors) may cause gynecomastia. Also, prolactin, thyroxine, cortisol, human chorionic gonadotropin, leptin and receptors for human chorionic gonadotropin, prolactin and luteinizing hormone localised in tissues of the male breast may participate in the etiopathogenesis of gynecomastia. Usually three types of gynecomastia are distinguished: physiological, idiopathic and pathological gynecomastia. The latter is the consequence of relative or absolute excess of oestrogens. In this paper, frequent as well as casuistic causes of gynecomastia will be described. A diagnosis of gynecomastia is usually possible after a palpation examination. Ultrasonographic, mammographic or histopathological examinations are useful in aiding diagnosis. The five degree scale devised by Tanner and Marshall is useful in estimating disease progression.     

Analysis of phospholipids and ornithine-containing lipids from Mesorhizobium spp

Polar lipid compositions of seven strains belonging to the four species of the Mesorhizobium genus were described. The lipid patterns of Mesorhizobium strains were very similar. Only quantitative differences were observed. Diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), and phosphatidylcholine (PC) were found to be the major phospholipids of the analysed bacteria. In addition, two methylated derivatives of PE were observed: phosphatidyl-N,N-dimethylethanolamine (DMPE) and phosphatidyl-N-monomethylethanolamine (MMPE). Polar head groups of those phospholipids were predominately acylated with lactobacillic (19:0 cyclopropane) acid. Ornithine-containing lipid (OL) was also identified. 3-hydroxy fatty acids found in the lipid preparations were derived exclusively from the ornithine lipid. 3-hydroxylactobacillic was the main acyl residue amide linked to the ornithine.     

Activity of AMP-Regulated Protein Kinase and AMP-Deaminase in the Heart of Mice Fed High-Fat Diet

AMP-regulated protein kinase (AMPK) is involved in numerous regulatory processes and its role in control of cardiac energy metabolism is particularly important. This activity could be affected by AMP-deaminase (AMPD) since substrate of AMPD is AMPK activator. Hearts of male mouse, fed for six weeks with normal or high-fat diet, were fractionated to enrich AMPK activity. Purified fraction was incubated with AMARA peptide for up to 5 minutes and then conversion of AMARA to pAMARA was determined by liquid chromatography—mass spectrometry (LC/MS) using mass detector. Activity of AMPK in heart was 0.038 ± 0.012 pmol/min/mg protein for mice fed high-fat diet and that was not different to control (0.032 ± 0.01 pmol/min/mg protein). We observed change in AMPD activity. It was 5.39 ± 1.5 nmol/mg tissue/min in heart of mice fed high-fat diet while in heart of mice fed low-fat diet it was 2.29 ± 0.32 nmol/mg tissue/min. Data we present indicate that while total AMPK activity is not changed decrease in AMPD activity may affect AMPK signaling in diabetic heart.     

Antibody and Plasmablast Response to 13-Valent Pneumococcal Conjugate Vaccine in Chronic Lymphocytic Leukemia Patients – Preliminary Report

Background

Chronic lymphocytic leukemia (CLL) leads to significant immune system dysfunction. The predominant clinical presentation in 50% of patients involves recurrent, often severe, infections. Infections are also the most common (60–80%) cause of deaths in CLL patients. The scope of infections varies with the clinical stage of the disease. Treatment-naive patients typically present with respiratory tract infections caused by encapsulated bacteria Streptococcus pneumoniae and Haemophilus influenzae. Since 2012, the 13-valent pneumococcal conjugate vaccine (PCV13) has been recommended in the United States and some EU countries for pneumococcal infection prevention in patients with CLL (besides the long-standing standard, 23-valent pneumococcal polysaccharide vaccine, PPV23). The aim of this study was to compare the immune response to PCV13 in 24 previously untreated CLL patients and healthy subjects.

Methods

Both groups were evaluated for: the levels of specific pneumococcal antibodies, the levels of IgG and IgG subclasses and selected peripheral blood lymphocyte subpopulations including the frequency of plasmablasts before and after immunization.

Results

Adequate response to vaccination, defined as an at least two-fold increase in specific pneumococcal antibody titers versus pre-vaccination baseline titers, was found in 58.3% of CLL patients and 100% of healthy subjects. Both the CLL group and the control group demonstrated a statistically significant increase in the IgG2 subclass levels following vaccination (P = 0.0301). After vaccination, the frequency of plasmablasts was significantly lower (P<0.0001) in CLL patients in comparison to that in controls. Patients who responded to vaccination had lower clinical stage of CLL as well as higher total IgG, and IgG2 subclass levels. No significant vaccine-related side effects were observed.

Conclusions

PCV13 vaccination in CLL patients is safe and induces an effective immune response in a considerable proportion of patients. To achieve an optimal vaccination response, the administration of PCV13 is recommended as soon as possible following CLL diagnosis.     

Genetic composition of interspecific potato somatic hybrids and autofused 4<Emphasis Type="Italic">x</Emphasis> plants evaluated by DArT and cytoplasmic DNA markers

Key message

Using DArT analysis, we demonstrated that all Solanum × michoacanum (+) S. tuberosum somatic hybrids contained all parental chromosomes. However, from 13.9 to 29.6 % of the markers from both parents were lost in the hybrids.

Abstract

Somatic hybrids are an interesting material for research of nucleus-cytoplasm interaction and sources of new nuclear and cytoplasmic combinations. Analyses of genomes of somatic hybrids are essential for studies on genome compatibility between species, its evolution and are important for their efficient exploitation. Diversity array technology (DArT) permits analysis of the composition of nuclear DNA of somatic hybrids. The nuclear genome compositions of 97 Solanum × michoacanum (+) S. tuberosum [mch (+) tbr] somatic hybrids from five fusion combinations and 11 autofused 4x mch were analyzed for the first time based on DArT markers. Out of 5358 DArT markers generated in a single assay, greater than 2000 markers were polymorphic between parents, of which more than 1500 have a known chromosomal location on potato genetic or physical map. DArT markers were distributed along the entire length of 12 chromosomes. We noticed elimination of markers of wild and tbr fusion components. The nuclear genome of individual somatic hybrids was diversified. Mch is a source of resistance to Phytophthora infestans. From 97 mch (+) tbr somatic hybrids, two hybrids and all 11 autofused 4x mch were resistant to P. infestans. The analysis of the structure of particular hybrids’ chromosomes indicated the presence of markers from both parental genomes as well as missing markers spread along the full length of the chromosome. Markers specific to chloroplast DNA and mitochondrial DNA were used for analysis of changes within the organellar genomes of somatic hybrids. Random and non-random segregations of organellar DNA were noted.