Estimating woody and herbaceous vegetation cover from time series satellite observations

In this paper we test a method to estimate the tree and grass vegetation cover over Australia from satellite-derived normalized difference vegetation index (NDVI) time series (monthly 1981–91, ≈5 km pixels) observations. The evergreen cover is assumed to track along the base of the NDVI time series, which is assumed to be equivalent to the woody vegetation cover. The base of the NDVI time series is estimated using modifications to a classical econometric model (i.e. time series is the sum of trend, seasonal and random components). Estimates of the average evergreen component during 1982–85 and 1986–89 were generally consistent with known vegetation distributions. Changes in evergreen cover were largely restricted to the south-west and south-east of Australia. Those changes were largely the result of differences in rainfall between the two periods. The proposed method for estimating woody vegetation cover is found to be generally robust. However, there are some regions where the grass (or pasture) is mostly evergreen. Some possible refinements are proposed to handle such cases.     

Blueberry flavonoids inhibit matrix metalloproteinase activity in DU145 human prostate cancer cells.

Regulation of the matrix metalloproteinases (MMPs), the major mediators of extracellular matrix (ECM) degradation, is crucial to regulate ECM proteolysis, which is important in metastasis. This study examined the effects of 3 flavonoid-enriched fractions (a crude fraction, an anthocyanin-enriched fraction, and a proanthocyanidin-enriched fraction), which were prepared from lowbush blueberries (Vaccinium angustifolium), on MMP activity in DU145 human prostate cancer cells in vitro. Using gelatin gel electrophoresis, MMP activity was evaluated from cells after 24-hr exposure to blueberry fractions. All fractions elicited an ability to decrease the activity of MMP-2 and MMP-9. Of the fractions tested, the proanthocyanidin-enriched fraction was found to be the most effective at inhibiting MMP activity in these cells. No induction of either necrotic or apoptotic cell death was noted in these cells in response to treatment with the blueberry fractions. These findings indicate that flavonoids from blueberry possess the ability to effectively decrease MMP activity, which may decrease overall ECM degradation. This ability may be important in controlling tumor metastasis formation.     

Allelic variants of Ly-5 in inbred and natural populations of mice

Allelic variants of Ly-5 in inbred commensal and other natural populations of mice were analyzed by patterns of restriction fragment length polymorphisms (RFLP) and Southern hybridization using an Ly-5 cDNA probe and by cell-surface staining with a panel of antibodies directed against polymorphic and nonpolymorphic Ly-5 determinants. New Ly-5 alleles were defined by RFLPs generated by both Eco RI and Bam HI restriction enzyme digests. The Mus musculus subspecies and other species within the genus Mus showed a strong correlation between allelic variants defined by restriction enzymes and serologic specificities. The data also suggest the conservation of the Ly-5 gene throughout the genus Mus.     

Production of trace levels of carbon monoxide during methanogenesis on acetate and methanol

Summary Production of trace levels of carbon monoxide was consistently observed in the off-gas of a laboratory anaerobic digester fed Waste Activated Sludge. Inocula from this digester was enriched for acetate and methanol utilizing methanogenic populations. These enriched inocula were then monitored in batch assays for carbon monoxide and hydrogen production. Results demonstrated that carbon monoxide is produced during methanogenesis on both substrates. Subsequent utilization of CO was observed to occur after methane production was essentially complete for the assays conducted with methanol. Carbon monoxide evolution during methanogenesis on acetate displayed a markedly different trend from that observed from methanol.     

The use of agarose bead culture for the regeneration of single cell-derived colonies from protoplasts isolated from suspension cultures of Humulus lupulus

A cell-wall digestion medium has been devised to isolate protoplasts from suspension cultures of Humulus lupulus. Conditions have been developed for colony formation from protoplasts and the plating efficiency determined in three types of agar and by two culture methods. Viable calli were produced only when protoplasts embedded in Seaplaque agarose were incubated in a defined liquid medium. HPLC analysis showed that none of the isolated colonies accumulated -acids.     

Consort Intrusion and Female Mate Choice in Japanese Macaques (Macaca fuscata)

Consort intrusion behavior has been proposed to largely function as a means of preventing or suppressing the reproductive activity of subordinate males. In the Japanese macaques of Arashiyama B troop this behavior was found to be ineffective in influencing female mate choice and affecting differential reproduction. Mainly directed towards the female of the pair intrusion resembled sexual solicitation and appeared to be an extension of consort behavior. Although the intruder male was almost always dominant over the other male, intrusion failed to provide priority of access to the estrous female as she most frequently chose to remain with her current partner. Copulations which were intruded upon were as likely to end in ejaculation as those which were undisturbed. Only a small proportion of intruder male-female pairs mated. Pairs that did mate were likely to have been in consort before or during the period in which intrusion occurred. No significant correlation was found between male rank order and number of possible females impregnated. Individual young, middle to lower ranking males were estimated to have been reproductively the most successful.     

Gene regulation during dedifferentiation in Dictyostelium discoideum

During development of Dictyostelium discoideum, cells acquire the capacity to rapidly recapitulate morphogenesis. Therefore, when cells at the loose aggregate stage are disaggregated and challenged to reaggregate, they do so in a tenth of the original time. If loose aggregate cells are disaggregated and resuspended in buffered dextrose solution (erasure medium), they retain the capacity of rapid recapitulation for 80 min, then completely lose this capacity in a single, synchronous step referred to as the "erasure event." The erasure event sets in motion a program of dedifferentiation during which cells lose developmentally acquired characteristics at different times. The erasure event is inhibited by the addition of 10(-4) M cAMP to erasure medium. The synthesis of 33 growth-associated polypeptides, the synthesis of 53 development-associated polypeptides, and the level of 2 development-associated RNAs have been monitored during the erasure program and in cultures inhibited from erasing by the addition of 10(-4) M cAMP. Growth-associated polypeptides begin to be resynthesized and development-associated polypeptides exhibit dramatic decreases in rate of synthesis at different times throughout the first 240 min in erasure medium. Inhibiting the erasure event with cAMP has no major effect in the resynthesis of the majority of growth-associated polypeptides. Only one growth-associated polypeptide, V28, is completely inhibited by cAMP, suggesting that it may play a role in the erasure process. In contrast, inhibiting the erasure event with cAMP has a marked effect on the synthesis of development-associated polypeptides, causing a dramatic reduction in the rate at which synthesis decreases for 6 polypeptides, and completely inhibits the decrease in the synthetic rate of 8 polypeptides. The two development-associated RNAs, 16G1 and 10C3, exhibit two distinctly different patterns of loss during erasure, but in both cases cAMP added at time zero of the erasure process dramatically retards or inhibits loss. In addition, when cAMP is added just prior to the erasure event, it inhibits the erasure event and stimulates a rapid increase in the level of 16G1 RNA back to the developmental level. The level of 16G1 RNA then remains at this level for at least 400 min. When cAMP is added after the erasure event, it causes a low, transient increase in the level of 16G1 RNA. These results are considered both in relation to the program of erasure, and in relation to the role of cAMP in the expression of developmental genes during the forward program of development.     

Modulation of water and urea transport in human red cells: Effects of pH and phloretin

Summary It has previously been shown by Macey and Farmer (Biochim. Biophys. Acta 211:104–106, 1970) that phloretin inhibits urea transport across the human red cell membrane yet has no effect on water transport. Jennings and Solomon (J. Gen. Physiol. 67:381–397, 1976) have shown that there are separate lipid and protein binding sites for phloretin on the red cell membrane. We have now found that urea transport is inhibited by phloretin binding to the lipids with aK ₁ of 25±8 m in reason-able agreement with theK _D of 54±5 m for lipid binding. These experiments show that lipid/protein interactions can alter the conformational state of the urea transport protein. Phloretin binding to the protein site also modulates red cell urea transport, but the modulation is opposed by the specific stilbene anion transport inhibitor, DIDS (4,4-diisothiocyano-2,2-stilbene disulfonate), suggesting a linkage between the urea transport protein and band 3. Neither the lipid nor the protein phloretin binding site has any significant effect on water transport. Water transport is, however, inhibited by up to 30% in a pH-dependent manner by DIDS binding, which suggests that the DIDS/band 3 complex can modulate water transport.     

Distribution of calcium ATPase in the sarcoplasmic reticulum of fast- and slow-twitch muscles determined with monoclonal antibodies

Summary Four monoclonal antibodies against the calcium ATPase in sarcoplasmic reticulum (SR) of rabbit fast-twitch skeletal muscle were characterized using SDS-PAGE, Western blots and immunofluorescence. The ultrastructural distribution of the antigens was determined using post-embedding immunolabeling. The antibodies recognized the calcium ATPase in the SR but not in transverse (T-) tubule or plasma membranes. The antibody, D12, had the same binding affinity for the calcium ATPase from fast-twitch (rabbit sternomastoid) and slow-twitch (rabbit soleus) fibers and the affinity fell by 30% after fixation for electron microscopy in both types of muscle fiber. Ultrastructural studies revealed that the density of D12 antibody binding to the terminal cisternae membrane of extensor digitorum longus (edl) and sternomastoid fibers was on average seven times greater than in the slow-twitch soleus and semimembranosus fibers. Since the affinity of the ATPase for the antibody was the same in SR from fast- and slow-twitch muscles, the concentration of calcium ATPase in the terminal cisternae membrane of fast-twitch fibers was seven times greater than in slow-twitch fibers. This conclusion was supported by the fact that the concentration of calcium ATPase in light SR membranes was six times greater in SR from fast-twitch fibers than in SR from slow-twitch fibers. The results provide strong evidence that the different calcium accumulation rates in mammalian fast- and slow-twitch muscles are due to different concentrations of calcium ATPase molecules in the SR membrane.