Change in gene abundance in the nitrogen biogeochemical cycle with temperature and nitrogen addition in Antarctic soils

The microbial community (bacterial, archaeal, and fungi) and eight genes involved in the nitrogen biogeochemical cycle (nifH, nitrogen fixation; bacterial and archaeal amoA, ammonia oxidation; narG, nitrate reduction; nirS, nirK, nitrite reduction; norB, nitric oxide reduction; and nosZ, nitrous oxide reduction) were quantitatively assessed in this study, via real-time PCR with DNA extracted from three Antarctic soils. Interestingly, AOB amoA was found to be more abundant than AOA amoA in Antarctic soils. The results of microcosm studies revealed that the fungal and archaeal communities were diminished in response to warming temperatures (10 °C) and that the archaeal community was less sensitive to nitrogen addition, which suggests that those two communities are well-adapted to colder temperatures. AOA amoA and norB genes were reduced with warming temperatures. The abundance of only the nifH and nirK genes increased with both warming and the addition of nitrogen. NirS-type denitrifying bacteria outnumbered NirK-type denitrifiers regardless of the treatment used. Interestingly, dramatic increases in both NirS and NirK-types denitrifiers were observed with nitrogen addition. NirK types increase with warming, but NirS-type denitrifiers tend to be less sensitive to warming. Our findings indicated that the Antarctic microbial nitrogen cycle could be dramatically altered by temperature and nitrogen, and that warming may be detrimental to the ammonia-oxidizing archaeal community. To the best of our knowledge, this is the first report to investigate genes associated with each process of the nitrogen biogeochemical cycle in an Antarctic terrestrial soil environment.     

Some ecological and physiological studies on bacteria isolated from salt-affected soils of Egypt.

Members of Bacillaceae, Rhizobiaceae, actinomycetes and others were isolated from cultivated and non-cultivated saline soils. The high population of bacteria and actinomycetes were almost coincided with the relatively high levels of organic matter whatever the degree of soil salinity. Bacillus stearothermophilus and B. subtilis were more frequently isolated than other Bacillus species. Most of Rhizobium isolates were salt tolerant being able to grow in media containing 3% and 6% NaCl. The abilities of different bacterial isolates to attack citrus pectin, soluble and insoluble forms of cellulose were also tested.     

Characterization of root-nodule bacteria indigenous in the salt-affected soils of Egypt by lipopolysaccharide,protein and plasmid profiles

Some characteristics of thirty isolates of root-nodule bacteria, indigenous in the salt-affected soil of Egypt, were studied. To recognize different isolates of these bacteria, the electrophoretic pattern of plasmids and of whole cell lipopolysaccharides (LPS) and proteins were analysed and compared using agarose gel electrophoresis (AGE) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), respectively. The bacteria showed patterns of LPS, protein and plasmid which varied among isolates of different plant species as among isolates of a single plant species. Based on LPS and protein profile analysis, isolates from root-nodules of broadbean and lupin plants were more diverse than isolates from root-nodules of berseem plant. Root-nodule bacteria of lupin and berseem were also less diverse than root-nodule bacteria of broadbean when compared on the basis of plasmid profiles. This result indicate that root-nodule bacteria of broadbean may have higher surviving ability in the salt-affected soil. Most isolates of the root-nodule bacteria synthesized specific LPS (smooth, ladder-like type) and protein, which were different from LPS and protein of other well-known (recognized) Rhizobium species. These specific forms of LPS and protein could be a prerequisite for the bacterial isolates to tolerate salt stress conditions of the salt-affected soils.     

Molecular diversity of peanut‐nodulating rhizobia in soils of Argentina

RSα sequencing is a valuable tool for identification of bacterial strains, and for evaluating the genetic structure of indigenous rhizobial populations. The purpose of this study was to evaluate, qualitatively, the presence or absence of RSα fragment in peanut‐nodulating strains isolated from plants grown at four sites in central Argentina. RSα fragment was found in only three of 26 indigenous strains, and in one of three inoculant strains analyzed. In contrast to results from studies of other symbiotic nitrogen‐fixing bacteria, such as soybean‐nodulating strains, no correlation was found between generation time and presence of RSα sequence. Phylogenetic analysis of the 16S rRNA gene sequence grouped peanut‐nodulating strains into two clusters, Bradyrhizobium japonicum vs. B. elkanii, and showed divergence among strains positive for RSα sequence. Our results confirm the genetic diversity previously reported for various peanut‐nodulating rhizobial strains, and indicate that the RSα fragment is not applicable as a marker or tool for competition assays at the field or ecological level. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Psychoneuroendocrine stress responses and mood as related to the menstrual cycle

Psychoneuroendocrine stress responses were studied in normally ovulating women in the follicular, ovulatory, and luteal phases of two consecutive menstrual cycles. Psychologic stress was induced by having the subjects perform a battery of cognitive tasks under time pressure. Blood samples were drawn after each session for radioimmunoassay of 17 beta-estradiol, progesterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, prolactin, cortisol, and androstenedione. Urine samples were obtained for estimation of adrenaline, noradrenaline, and cortisol. The results showed that psychoneuroendocrine stress responses as estimated by urinary excretion of adrenaline and noradrenaline varied significantly across the menstrual cycle, the highest values being obtained in the luteal phase. Self-reported mood and somatic symptoms showed distinct phase-related changes, with more negative mood states predominating in the luteal and menstrual phases and increased positive mood states in the follicular and ovulatory phases.     

Ultrastructural aspects of the follicular cells of the pars tuberalis in bats related to the seasonal cycle

The topography and structure of the follicular cells and the follicular cavity of the hypophyseal pars tuberalis (PT) were studied in adult hibernating bats (Pipistrellus pipistrellus and Rhinolophus ferrumequinum) of both sexes, during the annual seasonal cycle and the reproductive cycle. The follicular cells were found to be organized around a central cavity. They showed a polyhedral shape and apical microvilli protruding into central cavities. During hibernation, the follicular cells showed active cytoplasmic organelles, clusters of glycogen particles, and lipid droplets. In the supranuclear cytoplasm, 9+2 type cilia, some dense bodies, microvesicular vacuoles, and thin actin-like filaments (rather scarce during autumn) were detected. The contents of the follicular cavity showed well-defined ultrastructural seasonal characteristics, with a colloid-like aspect during awakening and a strongly granular aspect during autumn oestrus and mating. Positive staining for PAS and paraldehyde fuchsin, and a marked reaction to lectins PHA-L4, MAM, and RCA 60 suggested the presence of sialo-glycoproteins in the follicular cavities. Both follicular and endocrine PT-specific cells appeared to mark the boundary of follicular cavities. This finding suggests that the follicular cavity contents are comprised of both types of cells, rather than by cell fragmentation or degeneration products.     

Tracking errors related to cardiac cycle: a new approach

One-dimensional manual tracking was investigated in relation to cardiac activity. The task of the subjects was, by means of a joy-stick, to maintain a spotlight between two vertical lines moving horizontally across an oscilloscope screen. Error incidence was time-locked with respect to the cardiac cycle. Error rate was higher for faster (2-s trial periods) than for slower (3-s trial periods) target movement. Using linear-ramp and sinusoidal movements, it was demonstrated that error incidence is associated with positive and negative cardiac acceleration.     

Sleep patterns related to menstrual cycle phase and premenstrual affective symptoms

An ovulatory menstrual cycle is characterized by fluctuating levels of progesterone. Progesterone, a gonadal hormone known for its soporific and thermogenic effects, is present in negligible levels prior to ovulation and in high levels after ovulation. To describe and compare sleep patterns in relation to ovulatory cycles and premenstrual mood state, sleep was monitored in healthy women at two phases of the menstrual cycle. Results indicated that rapid-eye-movement (REM) latency was significantly shorter during the postovulatory (luteal) phase compared to the preovulatory (follicular) phase, but there was no significant difference in latency to sleep onset or the percentage of REM sleep. While there were no menstrual cycle phase differences in the percentages of various sleep stages, the women with negative affect symptoms during the premenstruum demonstrated significantly less delta sleep during both menstrual cycle phases in comparison with the asymptomatic subjects.     

Wheat streak mosaic virus genotypes introduced to Argentina are closely related to isolates from the American Pacific Northwest and Australia

Wheat streak mosaic virus (WSMV) was first detected in Argentina in 2002. Comparison of 78 WSMV coat protein sequences revealed that three Argentine isolates were closely related to isolates from the American Pacific Northwest (APNW) and Australia. Complete sequences were determined for one Argentine isolate, four APNW isolates, and three additional isolates from other regions of the USA. Comparison of these eight new sequences with five previously sequenced isolates of WSMV confirmed close affinity of WSMV from Argentina with APNW isolates. Collectively, these results indicate concurrent establishment of the same WSMV lineage in both Argentina and Australia.     

Oxygen uptake as related to work rate increment during cycle ergometer exercise

Summary We postulated that the commonly observed constant linear relationship between and work rate during cycle ergometry to exhaustion is fortuitous and not due to an unchanging cost of external work. Therefore we measured continuously in 10 healthy men during such exercise while varying the rate of work incrementation and analyzed by linear regression techniques the relationship between and work rate ( / wr). After excluding the first and last portions of each test we found the mean ±SD of the / wr in ml · min^–1· W^–1 to be 11.2±0.15, 10.2±0.16, and 8.8±0.15 for the 15, 30, and 60 W·min^–1 tests, respectively, expressed as ml·J^–1 the values were 0.187±0.0025, 0.170±0.0027 and 0.147±0.0025. The slopes of the lower halves of the 15 and 30 W·min^–1 tests were 9.9±0.2 ml·min^–1·W^–1 similar to the values for aerobic work reported by others. However the upper halves of the 15, 30, and 60 W·min^–1 tests demonstrated significant differences: 12.4±0.36 vs 10.5±0.31 vs 8.7±0.23 ml·min^–1·W^–1 respectively. We postulate that these systematic differences are due to two opposing influences: 1) the fraction of energy from anaerobic sources is larger in the brief 60 W·min^–1 tests and 2) the increased energy requirement per W of heavy work is evident especially in the long 15 W·min^–1 tests.     

The cell cycle and related concepts in cell proliferation

The epithelioid cell granuloma in high resistant tuberculoid (TT) leprosy was contrasted with the pure macrophage granuloma of anergic lepromatous leprosy (LL) by evaluating various immunological factors operating in these lesions. The immunoperoxidase technique using antisera to immunoglobulin IgG, IgM, complement C₃, C₃d and C₁q and other products of macrophage secretion, lysozyme, plasminogen, a₁ antitrypsin and C-reactive protein and of la antigens revealed peak levels in tissues of most of these factors in both types of granuloma. The tuberculoid response was linked to low antigenic load and Ia-like antigen and the lepromatous response was secondary to a high antigenic load in the absence of Ia antigen. Complement and other mediators were found intracellularly in both tuberculoid and lepromatous granulomas, but extracellilarly only in tuberculoid lesions. This may indicate local hypersensitivity in the tuberculoid granuloma. It is suggested that the mediators in LL macrophages remain bound to the lipids of mycobacterial degeneration in the phagocytic vacuole. Secretory cells were differently sited in the two types of granulomas: peripheral in epithelioid cell lesions and central around capillaries over the whole lesion in pure macrophage granulomas of LL. In tuberculoid leprosy many of the central vessels in the granuloma were obliterated. C₁q was found in fibroblasts. However, the marked absence of fibrosis in any of the lesions of leprosy, except following severe reactions, casts some doubt on the link which has been postulated between epithelioid cells and fibroblasts as an explanation of fibrosis in granulomas.     

动情期和动情间期小鼠输卵管中氧化应激和抗氧化基因表达差异

目的观察昆明(Kunming,KM)小鼠输卵管中氧化应激和抗氧化基因的表达是否随动情周期而改变。方法分别取动情期和动情间期小鼠输卵管进行RNA提取,用PCR芯片检测氧化应激和抗氧化基因表达的差别,然后用Real Time PCR对差异表达基因进一步验证。结果与动情间期比较,动情期小鼠输卵管中NADPH氧化酶1(NADPH oxidase1,NOX1)、谷胱甘肽过氧化物酶2(glutathion peroxidase 2,GPX2)、超氧化物歧化酶3(superoxide dismutase 3,SOD3)、一氧化氮合酶2(nitric oxide synthase 2,NOS2)等4个基因表达上调。结论动情期小鼠输卵管中NOX1、GPX2、SOD3和NOS2等4个基因表达上调,提示其可能参与维持动情期小鼠输卵管腔内适度的活性氧自由基(reactive oxygen species,ROS)和一氧化氮(nitric oxide,NO)水平,为卵子受精和早胚发育提供必要第二信号分子。     

Endocrinology: The sex of the baby may be related to the length of the follicular phase in the conception cycle

In a prospective study of normal couples discontinuing contraceptionto begin a pregnancy, the days of ovulation were estimated byhormonal assay of daily urine specimens. No hormonal interventionswere used. Length of the follicular phase (from onset of mensesto ovulation) was found to be related to the sex of the babyamong 133 pregnancies that survived to delivery. Conceptioncycles with short follicular phases (early ovulation) tendedto produce boys, while those with long follicular phases tendedto produce girls. This relationship is consistent with otherdata and could explain sex-related differences in the lengthof gestation and the observed excess of same-sex pairs amongdizygotic twins.     

Steroid levels in ovarian follicular fluid related to follicle size and health status during the normal menstrual cycle in women

Steroid levels in 308 follicular fluid (FF) aspirates obtained during laparotomy from 116 women with normal ovarian function were related to the size (greater than 1 mm diameter) and health of the aspirated follicles and the phase of the menstrual cycle in which the FF sampling was done. The percentage of granulosa cells (g.c.) in the DNA S phase (S fraction) in each FF aspirate was determined by flow cytometry and used to classify non-pre-ovulatory follicles as healthy or atretic. A significant correlation between g.c. DNA S fraction and concentration of oestradiol (E2) in FF (FF-E2) was found, restricted to non-pre-ovulatory follicles with diameter greater than 6 mm. This evidence supports the notion that E2 acts as a local g.c. mitogen in these follicles, but also indicates that other factors may be required to stimulate g.c. proliferation in the smaller antral follicles (less than or equal to 6 mm diameter). The pattern of steroids in FF of healthy follicles was related to the stage of follicular development, being predominantly 'androgenic' in small follicles (less than or equal to 6 mm diameter), 'oestrogenic' in larger non-pre-ovulatory follicles (greater than 6 mm diameter) and 'progestagenic' in pre-ovulatory follicles. In contrast, atretic follicles of all sizes (2-13 mm diameter) exhibited an 'androgenic' pattern of steroids in FF. The intrafollicular hormonal milieu in the larger healthy non-pre-ovulatory and in pre-ovulatory follicles varied as a function of menstrual cycle phase, whereas that in small follicles (healthy as well as atretic) and in larger atretic follicles remained 'androgenic' through all the phases of the cycle.(ABSTRACT TRUNCATED AT 250 WORDS)