Isolation and partial characterization of culturable endophytic Arthrobacter spp. from leaves of maize (Zea mays L.)

The presence and diversity of the endophytic Arthrobacter species are relatively uninvestigated. We determined the genotypic and physiological diversity of the endophytic Arthrobacter spp. isolated from the interior leaf tissues of four out of six maize cultivars tested, all of which were collected under field conditions. Strains A7 and A9 isolated from Król cultivar and strain A23 isolated from KB1902 cultivar were identified as A. nicotinovorans. Strains A18, A22 and A34 identified as A. nitroguajacolicus were isolated from KB1903, KB1902 and Cyrkon cultivars respectively. Isolated strains tolerate the presence of o-coumaric, p-coumaric, chlorogenic, and ferulic acids in a concentration of at least two times higher than naturally occurring in maize tissue. The presence of the nitrogenase reductase gene nifH, a marker of biological nitrogen fixation, was determined in only two strains of A. nitroguajacolicus A18 and A34. None of the tested strains released compounds inhibiting in vitro the growth of the fungi Fusarium moniliforme and F. graminearum, pathogenic to maize. Seed inoculations with the A. nicotinovorans strain A7 suppressed the development of seedlings of four maize cultivars, which were not colonized by this species of bacteria, but stimulated the development of seedlings of the host-cultivar Król. Also, the A. nitroguajacolicus strain A18, which was applied as seed treatment, suppressed the development of seedlings of three maize cultivars, which were not colonized by this species of bacteria. The occurrence of endophytic A. nicotinovorans and A. nitroguajacolicus inhabiting interior tissues of maize leaves of specific maize cultivars is a first report in literature.

Lack of nifH gene in some endophytic bacteria isolated on RC solid medium

Presence of endophytic bacteria was reported in many crops including maize (Zea mays L.). Endophytes play a significant role in plant nutrient and pesticide uptake. Application of endophytic bacteria is a goal of sustainable agriculture. Occurrence of Azospirillum strains is often reported as tissue inhabiting bacteria of maize. The biological N2-fixation is one of most important processes assigned to this bacteria. The objective of this study was to examine the biodiversity of Azospirillum spp. isolated from the leaves of 6 cultivars of Zea mays L.. They were cultivated on two experimental fields at Smolice and Kobierzyce, (Poland). Strains of Azospirillum spp. were isolated on the solid RC medium. Forty four isolates grown as a small intensive red colonies were selected. To verify ability to N2-fixation isolates were analyzed based on nifH gene presence. Presence of nifH gene was tested using PCR method with PolF and PolR universal degenerate primers. The presence of nifH gene was found in 6 tested strains isolated from leaves of 3 cultivars (Cyrkon, Kosmo230, KB2704) from Smolice location, only. Our results suggest that selection of Azospirillum-like strains on RC solid medium based on appearance of colony is not correlated with theirs ability to nitrogen fixation or used degenerated primers (PolF, PolR) are not universal enough.

The usefulness of testicular atrophy index in the assessment of undescended testicle--preliminary report

PURPOSE

Cryptorchidism affects 2-8% of male newborns. There is a controversy regarding timing of surgery as well as indications for orchiopexy in boys with retractile testicle. The aim of this study was to evaluate the clinical usefulness of testicular atrophy index (TAI) as a criterion of qualifying patients with undescended testes for surgery as well as of monitoring the results of treatment.

MATERIAL AND METHODS

In 1999-2000, 105 cryptorchid boys, aged 1 to 15 years (mean 4.8) underwent unilateral orchiopexy. Dimensions and volume of testes were measured by means of scrotal US and TAI was calculated before and 1 year after surgery.

RESULTS

Pre- and postoperative scrotal US measurements were analyzed in 35 boys divided into five age dependent groups. The preoperative TAI values ranged from 27.1% to 52.8%. The biggest loss in volume of affected testis was found in boys aged 4 to 10 years (35.4% to 52.8%). The TAI values measured one year after orchiopexy were lower than preoperative ones. Significant difference in TAI values, ranging from 18.16% to 36.43% were observed in boys between 2 and 10 years (p < 0.001). In the youngest (0-2 yrs) and the oldest boys (> 10 yrs) the difference was not statistically significant.

CONCLUSIONS

The testicular atrophy index (TAI) proved to be a valuable and objective tool for qualifying patients with undescended testes for surgery as well as for monitoring the results of treatment. Its value of 20% and more should be considered an indication for surgery in boys with retractile testes.

[Endocarditis lenta--a problematic disease]

4 endocarditis lenta cases with negative blood cultures are reported: 3 patients with risk heart lesions and 1 subject with no predisposing cardiac condition. The mean age of the patients was 53.7 years. Based on the cases reported the following items are discussed: evolution of the clinical syndrome, diagnostic difficulties, problem of negative blood cultures, therapeutic procedure.

Discrepancy between self-reported and actual caloric intake and exercise in obese subjects

BACKGROUND AND METHODS

Some obese subjects repeatedly fail to lose weight even though they report restricting their caloric intake to less than 1200 kcal per day. We studied two explanations for this apparent resistance to diet--low total energy expenditure and underreporting of caloric intake--in 224 consecutive obese subjects presenting for treatment. Group 1 consisted of nine women and one man with a history of diet resistance in whom we evaluated total energy expenditure and its main thermogenic components and actual energy intake for 14 days by indirect calorimetry and analysis of body composition. Group 2, subgroups of which served as controls in the various evaluations, consisted of 67 women and 13 men with no history of diet resistance.

RESULTS

Total energy expenditure and resting metabolic rate in the subjects with diet resistance (group 1) were within 5 percent of the predicted values for body composition, and there was no significant difference between groups 1 and 2 in the thermic effects of food and exercise. Low energy expenditure was thus excluded as a mechanism of self-reported diet resistance. In contrast, the subjects in group 1 underreported their actual food intake by an average (+/- SD) of 47 +/- 16 percent and overreported their physical activity by 51 +/- 75 percent. Although the subjects in group 1 had no distinct psychopathologic characteristics, they perceived a genetic cause for their obesity, used thyroid medication at a high frequency, and described their eating behavior as relatively normal (all P < 0.05 as compared with group 2).

CONCLUSIONS

The failure of some obese subjects to lose weight while eating a diet they report as low in calories is due to an energy intake substantially higher than reported and an overestimation of physical activity, not to an abnormality in thermogenesis.