Semen quality and reproductive endocrine function with regard to blood cadmium in Croatian male subjects

In 123 Croatian men with no occupational exposure to metals, the influence of cadmium on reproductive parameters was examined after adjusting for age, smoking, alcohol, and biomarkers of lead, copper, zinc, and selenium. The following variables were measured: blood cadmium (BCd), blood lead (BPb), activity of -aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin, serum copper (SCu), serum zinc (SZn), serum selenium (SSe), activity of glutathione peroxidase (GPx) in blood, testis size, semen quality (including sperm concentration, motility, viability, and morphology), indicators in seminal fluid (the lactate dehydrogenase isoenzyme LDH-C₄, fructose, zinc, acid phosphatase, and citric acid), and hormones in serum (follicle-stimulating hormone – FSH, luteinizing hormone, prolactin, testosterone, and estradiol). The median and range BCd values were 2.94 (0.49-11.93) g/L in 61 smokers and 0.59 (0.20-3.71) g/L in 62 nonsmokers (p<0.0001). Smoking habits (cigarettes/day) highly significantly correlated with BCd (p<0.0001). After adjusting for potential confounding variables by multiple regression, BCd was significantly associated with a decrease in testis size (p<0.03) and an increase in serum estradiol (p<0.005), FSH (p<0.03), and testosterone (p<0.04). Smoking was significantly associated with a decrease in serum prolactin (p<0.006) and LDH-C₄ in seminal fluid (p<0.03). Several reproductive parameters were significantly associated with BPb and ALAD, biomarkers of lead, and/or with SCu, SZn, SSe, and GPx. The necessity of controlling for various metals, and other potential confounders when assessing the influence of a particular metal on reproductive function in men, is emphasized.     

Differential effect of lentil feeding on proteosynthesis rates in the large intestine, liver and muscle of rats

The aim of this work was to test the hypothesis that the trophic effect of lentil feeding on large intestine results from a stimulation of protein synthesis and to determine whether it interferes with protein metabolism in other splanchnic or peripheral organs. Two groups of growing Sprague Dawley male rats were pair-fed iso-caloric iso-nitrogenous balanced diets containing either cooked lentils (Lens esculenta puyensis) or casein as unique protein source. Protein synthesis rates were measured in vivo, in large intestine, liver and gastrocnemius at the postprandial state. In large intestine, protein and ribonucleic acid contents were higher in the lentil-fed group than in the control group, and the amount of proteins synthesized was also higher (+57%). By contrast, liver protein and ribonucleic acid contents as well as protein synthesis rates were significantly lower in the lentil-fed group than in the control group. In the gastrocnemius muscle protein and ribonucleic acid contents were significantly lower and the amount of protein synthesized was also lower (-18%) in the lentil fed group than in the control group. This study suggests that stimulation of protein synthesis in the large intestine is compensated for by a decrease in liver and muscle.     

Wood dust exposure in wood industry and forestry

The aim of the study was to determine occupational exposure in Croatian wood processing industry and forest workers to harmful effects of wood dust on the risk of nose, nasal cavity and lung carcinoma. Mass concentrations of respirable particles and total wood dust were measured at two wood processing plants, three woodwork shops, and one lumbering site, where 225 total wood dust samples and 221 respirable particle samples were collected. Wood dust mass concentration was determined by the gravimetric method. Mass concentrations exceeding total wood dust maximal allowed concentration (MAC, 3 mg/m3) were measured for beechwood and oakwood dust in 38% (79/206) of study samples from wood processing facilities (plants and woodwork shops). Mass concentrations of respirable particles exceeding MAC (1 mg/m3) were recorded in 24% (48/202) of samples from wood processing facilities (mean 2.38 +/- 2.08 mg/m3 in plants and 3.6 +/- 2.22 mg/m3 in woodwork shops). Thus, 13% (27/206) of work sites in wood processing facilities failed to meet health criteria according to European guidelines. Launching of measures to reduce wood dust emission to the work area is recommended.     

Segregation analysis of systolic and diastolic blood pressure in Middle Dalmatia Island population

A complex segregation analysis of systolic and diastolic blood pressure has been performed on pedigree data from rural populations inhabiting Middle Dalmatian islands of Brac, Hvar and Korcula and the Peljesac peninsula. The purpose of the performed analysis was to possibly elucidate a signal of a large-effect gene responsible for high prevalence of hypertension present in this population (the age-adjusted prevalence of developed hypertension being 31.82% in males and 28.23% in females). The analysis was performed on a sample of 389 two- and three-generation families consisting of 2 to 19 observed individuals (1126 examinees in total, 526 males and 600 females, aged 17 to 83). Since the examinees were randomly selected from census data encompassing 22.6% of the total population--the family relations having been established afterwards--the selected sample can be considered representative for the examined populations. By applying the usual transmission probability tests, the major gene model has been accepted for systolic as well as for diastolic blood pressure. The most parsimonious models showed that: (a) inheritance of blood pressure in the Middle Dalmatia population can be attributed to the effect of a major gene responsible for 34% (systolic) and 36% (diastolic) blood pressure variation; (b) alleles of that major gene act in co-dominant fashion; (c) allele frequency for high blood pressure (A2) is 18% (systolic) and 15% (diastolic blood pressure); and (d) the residual (non-major gene) familial correlation is negligible and can be constrained to zero. Since the results are also indicating heterogeneity within the sample in the genetic determination of the systolic blood pressure, the obtained results thus justify further search for the most promising subpopulation for incoming genetic epidemiological investigations of hypertension.     

Characterization of a molt-inhibiting hormone (MIH) of the crayfish, Orconectes limosus, by cDNA cloning and mass spectrometric analysis

The structure of the precursor of a molt-inhibiting hormone (MIH) of the American crayfish, Orconectes limosus was determined by cloning of a cDNA based on RNA from the neurosecretory perikarya of the X-organ in the eyestalk ganglia. The open reading frame includes the complete precursor sequence, consisting of a signal peptide of 29, and the MIH sequence of 77 amino acids. In addition, the mature peptide was isolated by HPLC from the neurohemal sinus gland and analyzed by ESI-MS and MALDI-TOF-MS peptide mapping. This showed that the mature peptide (Mass 8664.29 Da) consists of only 75 amino acids, having Ala75-NH2 as C-terminus. Thus, C-terminal Arg77 of the precursor is removed during processing, and Gly76 serves as an amide donor. Sequence comparison confirms this peptide as a novel member of the large family, which includes crustacean hyperglycaemic hormone (CHH), MIH and gonad (vitellogenesis)-inhibiting hormone (GIH/VIH). The lack of a CPRP (CHH-precursor related peptide) in the hormone precursor, the size and specific sequence characteristics show that Orl MIH belongs to the MIH/GIH(VIH) subgroup of this larger family. Comparison with the MIH of Procambarus clarkii, the only other MIH that has thus far been identified in freshwater crayfish, shows extremely high sequence conservation. Both MIHs differ in only one amino acid residue ( approximately 99% identity), whereas the sequence identity to several other known MIHs is between 40 and 46%.     

Isolation of lactococcal prolate phage-phage recombinants by an enrichment strategy reveals two novel host range determinants

Virulent lactococcal prolate (or c2-like) phages are the second most common phage group that causes fermentation failure in the dairy industry. We have mapped two host range determinants in two lactococcal prolate phages, c2 and 923, for the host strains MG1363 and 112. Each phage replicates on only one of the two host strains: c2 on MG1363 and 923 on 112. Phage-phage recombinants that replicated on both strains were isolated by a new method that does not require direct selection but rather employs an enrichment protocol. After initial mixed infection of strain 112, two rotations, the first of which was carried out on strain MG1363 and the second on 112, permitted continuous amplification of double-plating recombinants while rendering one of the parent phages unamplified in each of the two rotations. Mapping of the recombination endpoints showed that the presence of the N-terminal two-thirds of the tail protein L10 of phage c2 and a 1,562-bp cosR-terminal fragment of phage 923 genome overcame blocks of infection in strains MG1363 and 112, respectively. Both infection inhibition mechanisms act at the stage of DNA entry; in strain MG1363, the infection block acts early, before phage DNA enters the cytoplasm, and in strain 112, it acts late, after most of the DNA has entered the cell but before it undergoes cos-end ligation. These are the first reported host range determinants in bacteriophage of lactic acid bacteria required for overcoming inhibition of infection at the stage of DNA entry and cos-end ligation.     

Identification of neuropeptides from the sinus gland of the crayfish Orconectes limosus using nanoscale on-line liquid chromatography tandem mass spectrometry

In this article, a novel and sensitive analytical strategy for direct characterization of neuropeptides from the X-Organ-sinus gland neurosecretory system of the crayfish Orconectes limosus is presented. A desalted extract corresponding to 0.5 sinus gland equivalents was analyzed in a nanoflow liquid chromatography system coupled to quadrupole time-of-flight tandem mass spectrometry (nanoLC-QTOF MS/MS). The existence and structural identity of four crustacean hyperglycemic hormone precursor-related peptide variants and two new genetic variants of the pigment-dispersing hormone, not detected by conventional chromatographic systems, molecular cloning, or immunochemical methods before, was revealed. The here-presented approach of the combined LC-QTOF MS/MS technique is a powerful tool to discover new peptide hormones in biological systems, due to its sensitivity, accuracy, and speed.     

Spheroidal carbonaceous particle record in sediments of a small reservoir

The main aims of this study were to determine whether reservoir sediments provide good temporal records of atmospherically deposited spheroidal carbonaceous particles (SCPs), and to examine their spatial distribution within the reservoir. SCPs are produced solely by fossil-fuel burning and are good indicators of the extent of industrial pollution. The site chosen for the study was Drásov Reservoir in the Czech Republic. Sediment cores were taken along two transects within the reservoir. The results suggest that wind- and inlet-induced currents have an important influence on both SCP and sediment distribution in the reservoir, and that the distribution of SCPs is different to that of sediments. The SCP records were most reliable in the down-wind area of the reservoir, and although most detailed SCP record was contained in a deep-water core near the dam, records in shallower-water cores from the down-wind side of the reservoir were also good. The correlation between SCP accumulation rates and solid emissions from local sources was very good (Spearman R=0.867, p=0.001).%     

Benthic macroinvertebrates associated with four species of macrophytes

Benthic macroinvertebrates associated with four species of macrophytes (Nymphoides peltata, Ceratophyllum demersum, Polygonum amphibium and Carex sp.) were investigated during two growing seasons (2001 and 2002) in the slow-flowing Čonakut Channel in the Kopački rit Nature Park in Croatia. A total of 31 macroinvertebrate taxa were found. C. demersum, a submerged plant with dissected leaves, supported the highest macroinvertebrate abundance, almost seven times more than N. peltata, a floating plant with undissected leaves, which harboured the lowest abundance during the research period. Chironomidae larvae (50–83%) and Oligochaeta (14–46%) were the most abundant groups recorded on all macrophyte species. Water-level fluctuation, because of its influence on the appearance and growth of aquatic vegetation, and the trophic state of water within the macrophyte stands seemed to be the main factors which affected the taxonomic composition and abundance of macroinvertebrates.