Effects of long-term experimental warming on plants and soil microbes in a cool temperate semi-natural grassland in Japan

To clarify the effects of long-term warming on ecosystem matter cycling, we conducted an in situ 7-year experimental warming (2009–2015) using infrared heaters in a cool temperate semi-natural grassland in Japan. We measured plant aboveground biomass, soil total C and N, soil inorganic N (NH₄ ⁺-N and NO₃ ^?-N), and soil microbial biomass for 7 years (2009–2015). We also measured heterotrophic respiration for 2 years (2013–2014) and assessed net N mineralization and nitrification in 2015. We found that warming immediately increased plant aboveground biomass, but this effect ceased in 2013. However, the soil microbial biomass was continuously depressed by warming. Soil inorganic N concentrations in warmed plots substantially increased in the later years of the experiment (2013–2015) and the potential net N mineralization rate was also higher than in the earlier years. In contrast, heterotrophic respiration decreased with warming in 2013–2014. Our observations indicate that long-term warming has a contrasting effect on plants and soil microbes. In addition, the warming could have different effects on subterranean C and N cycling. To enhance the accuracy of estimation of future climate change, it is essential to continuously observe the warming effects on ecosystems and to focus on the change in subterranean C and N cycling.     

Transient generation of hydrogen peroxide is responsible for carcinostatic effects of hydrogen combined with platinum nanocolloid,together with increases intracellular ROS,DNA cleavages,and proportion of G2/M-phase

In our previous study, we demonstrated that combined treatment with hydrogen (H₂) and platinum nanocolloid (Pt-nc) exerted markedly antiproliferative effects on cancer cells compared with each treatment alone. However, because the related mechanisms remain unclear, we investigated carcinostatic mechanisms of the combined treatment with H₂ + Pt-nc. Significant suppression of cell proliferation was confirmed at 52?h following combined treatment, and the similar effect was also observed by the 30- or 40-min transient treatment with H₂?+?Pt-nc. The transient treatments led to changes in cell size and morphology, loss of microvilli, and apoptosis-like cell death at 120 h after treatment. Moreover, transient combined treatment with H₂?+?Pt-nc induced cell-cycle arrest, as reflected by decreased proportions of G1-phase cells and accumulation of G2/M-phase cells. In contrast, intracellular peroxide levels were temporarily and significantly increased immediately after H₂?+?Pt-nc treatment but not after treatment with H₂ or Pt-nc alone. Additionally, combined treatment-induced carcinostatic effects were significantly diminished in the presence of catalase, and marked hydrogen peroxide (H₂O₂) generation was confirmed after mixing Pt-nc into cell culture media containing a high concentration of H₂. These changes are in agreement with the results that carcinostatic effects were induced after only 40 min of treatment with H₂?+?Pt-nc. Thus, transient and marked generation of H₂O₂ is responsible for the carcinostatic effects of combined treatment with H₂?+?Pt-nc.     

Effects of herbivory by chrysomelid beetles on the growth and survival ofRumex plants

The effects of herbivory by the guild of chrysomelid beetles on the growth and survival ofRumex plants were examined in relation to the distribution and size of the plants. Gastrophysa atrocyanea never appeared on solitary plants whereasMantula clavareaui showed even utilization of solitary and clumped plants.Galerucella vittaticollis utilized large solitary plants most frequently. In patches of the host plants, the frequency of withering of the aerial parts was higher on small plants. The regrowth rate was higher when the aerial parts withered in spring than in summer. In patches of the host plants, the regrowth rate was higher on small plants. On the other hand, it was lower on small solitary plants than on large solitary plants and small plants in patches. In large plants, no difference in survival rate was recognized between solitary and clumped plants, because both the frequency of withering of the aerial parts and the regrowth rate were lower in clumped than solitary plants. The high vigor against intense herbivory by the chrysomelid beetles brought on the delay in the phenology ofRumex plants. This shift permits in parts the existence ofG. vittaticollis in mid summer. The temporal and spatial interactions between herbivore guild and the host plants were discussed.     

A new lymphocyte alloantigen (Ly-10) controlled by a gene linked to theLyt-1 locus

Spleen cells from a (BALB/cxC57BL/6)F₁ mouse immunized with CBA/J spleen cells were fused with the myeloma cell line NS-1. One of the six established hybrid cell lines continuously secreted antibody that recognized a new antigenic specificity, tentatively called Ly-10.1. This newly found antigen is expressed on thymocytes, on splenic T and B cells, on bone-marrow cells, and on the cells derived from brain, kidney and liver. It is also expressed on a continuous cell line, 416B, with stem-cell characteristics. The unique tissue distribution and, furthermore, a distinct strain distribution pattern distinguishes Ly-10.1 from any known murine lymphocyte alloantigen. On the basis of reactivity with cells of the C57BL/6-Lyt-1^a congenic strain, one gene governing Ly-10 expression is assigned to the Lyt-1 region of chromosome 19.We chose the notation Ly-10 rather than Ly-9 to allow for a future decision that Lgp 100 (Ledbetter et al. 1979) should be renamed Ly-9.     

New mouse immunoglobulin a heavy chain allotype specificities detected using the hybridoma-derived IgA of I/St Mice

Immunizations of C57BL/6 and A mice with IgA derived from the I/St mouse strain yield alloantisera which detect two allotypic determinants of immunoglobulin A. The two determinants display discrete strain distributions. The first, identified by the alloantiserum C57BL/6 anti-IgA of I/St strain hybridoma ID150, follows the Igh ^c haplotype, and the second, identified by the alloantiserum A anti-IgA of I/St strain hybridoma ID150, correlates with Igh ^c and Igh ^c haplotypes. Absorption with monoclonal IgM, which has the same idiotype as the ID150 IgA clone, removed idiotype-specific antibodies from both alloantisera. The remaining antibodies are directed against determinants associated with the chain constant region, as shown by absorption with monoclonal IgA. By use of recombinant inbred strains of mice and mice congenic at the Igh locus, the loci controlling both C allotypic determinants have been mapped to the Igh region on chromosome 12.Abbreviations used in this paper Ig immunoglobulin - NMS normal mouse serum (sera) The genetic nomenclature of Green (1979) for mouse immunoglobulin loci was used in this report.     

A new mouse cell-surface antigen (Ly-m18) defined by a monoclonal antibody

Spleen cells from C3H/An mice immunized with spleen cells of C57BL/6-H-2 ^k mice were fused with myeloma cell line NS.1. One established hybrid cell line continuously secreted antibody that recognized a new surface antigen provisionally called Ly-m18. The new alloantigen is expressed on 90 percent of thymus cells, 55 percent of spleen cells, and 45 percent of either lymphnode or bone-marrow cells. It is also expressed on cells derived from brain, kidney, and liver. Fifty percent of either peripheral T or B cells express the Ly-m18 antigen, and some tumor cell lines with T, B, pre-B or stem cell characteristics are Ly-m18 (+). The strain distribution pattern distinguishes Ly-m1 8 antigen from all other murine lymphocyte alloantigens. The typing data of two sets of CXB and AKXL recombinant inbred strains indicate that the Ly-m18 gene is linked to the Ltw-2 locus which has not yet been assigned to a chromosome.Abbreviations used in this paper RI recombinant inbred - Con-A concanavalin A - LPS lipopolysaccharide - MLR mixed lymphocyte reaction The prefix m (monoclonal) is used following a suggestion by Klein and co-workers (1979).     

A method for estimating natural survival rate and mean fecundity of an adult insect population by dissecting the female reproductive organs

Several problems were discussed in relation toMacDonald' s method (MacDonald , 1957) for estimating the survival rate of a natural population of adults with varying survival rates and unstable age structure.

1. Random samplings with a fixed sampling ratio and an appropriate census interval is pre-requisite during the occurrence of the adults.
2. At each sampling, female adults are dissected to know the ratio, p_i, of nulliparous females in ith sample (i=0, 1, 2, 3, …,). The Σn_ip_i/Σn_i gives an estimate of the ratio, Fα/F, of nulliparous females in the population where n_i refers to the population size on ith census date. If a constant daily survival rate is assumed, the daily survival rate is estimated from equation (4′). When the survival rate is not constant over the period of adult occurrence, e. g. before and after the initiation of oviposition, the survival rate during pre-ovipositional period is estimated by equation (4″).
3. Decision of an economic census interval to obtain a reliable estimate of the ratio, Fα/F, is depending on the form of emergence curve, particularly on its duration and the length of pre-ovipositional period. If the normal distribution can be assumed for the emergence curve, an interval less than one third of the emergence period is recommended. Concerning with insects having a long pre-ovipositional period, a census interval which exceeds one third of the emergence period still gives a good estimate of Fα/F.
4. The mean realized fecundity of some kind of insects can be estimated by equation (5′ or 5″) using the estimates obtained by the present method.

     

Solvent drag measurement of transcellular and basolateral membrane NaCl reflection coefficient in kidney proximal tubule

The NaCl reflection coefficient in proximal tubule has important implications for the mechanisms of near isosmotic volume reabsorption. A new fluorescence method was developed and applied to measure the transepithelial (sigma NaClTE) and basolateral membrane (sigma NaClcl) NaCl reflection coefficients in the isolated proximal straight tubule from rabbit kidney. For sigma NaClTE measurement, tubules were perfused with buffers containing 0 Cl, the Cl-sensitive fluorescent indicator 6-methoxy-N-[3-sulfopropyl] quinolinium and a Cl-insensitive indicator fluorescein sulfonate, and bathed in buffers of differing cryoscopic osmolalities containing NaCl. The transepithelial Cl gradient along the length of the tubule was measured in the steady state by a quantitative ratio imaging technique. A mathematical model based on the Kedem-Katchalsky equations was developed to calculate the axial profile of [Cl] from tubule geometry, lumen flow, water (Pf) and NaCl (PNaCl) permeabilities, and sigma NaClTE. A fit of experimental results to the model gave PNaCl = (2.25 +/- 0.2) x 10(-5) cm/s and sigma NaClTE = 0.98 +/- 0.03 at 23 degrees C. For measurement of sigma NaClbl, tubule cells were loaded with SPQ in the absence of Cl. NaCl solvent drag was measured from the time course of NaCl influx in response to rapid (less than 1 s) Cl addition to the bath solution. With bath-to-cell cryoscopic osmotic gradients of 0, -60, and +30 mosmol, initial Cl influx was 1.23, 1.10, and 1.25 mM/s; a fit to a mathematical model gave sigma NaClbl = 0.97 +/- 0.04. These results indicate absence of NaCl solvent drag in rabbit proximal tubule. The implications of these findings for water and NaCl movement in proximal tubule are evaluated.