Area and the rapid radiation of Hawaiian Bidens (Asteraceae)

Aim To estimate the rate of adaptive radiation of endemic Hawaiian Bidens and to compare their diversification rates with those of other plants in Hawaii and elsewhere with rapid rates of radiation. Location Hawaii. Methods Fifty‐nine samples representing all 19 Hawaiian species, six Hawaiian subspecies, two Hawaiian hybrids and an additional two Central American and two African Bidens species had their DNA extracted, amplified by polymerase chain reaction and sequenced for four chloroplast and two nuclear loci, resulting in a total of approximately 5400 base pairs per individual. Internal transcribed spacer sequences for additional outgroup taxa, including 13 non‐Hawaiian Bidens, were obtained from GenBank. Phylogenetic relationships were assessed by maximum likelihood and Bayesian inference. The age of the most recent common ancestor and diversification rates of Hawaiian Bidens were estimated using the methods of previously published studies to allow for direct comparison with other studies. Calculations were made on a per‐unit‐area basis. Results We estimate the age of the Hawaiian clade to be 1.3–3.1 million years old, with an estimated diversification rate of 0.3–2.3 species/million years and 4.8 × 10^?5 to 1.3 × 10^?4 species Myr^?1 km^?2. Bidens species are found in Europe, Africa, Asia and North and South America, but the Hawaiian species have greater diversity of growth form, floral morphology, dispersal mode and habitat type than observed in the rest of the genus world‐wide. Despite this diversity, we found little genetic differentiation among the Hawaiian species. This is similar to the results from other molecular studies on Hawaiian plant taxa, including others with great morphological variability (e.g. silverswords, lobeliads and mints). Main conclusions On a per‐unit‐area basis, Hawaiian Bidens have among the highest rates of speciation for plant radiations documented to date. The rapid diversification within such a small area was probably facilitated by the habitat diversity of the Hawaiian Islands and the adaptive loss of dispersal potential. Our findings point to the need to consider the spatial context of diversification – specifically, the relative scale of habitable area, environmental heterogeneity and dispersal ability – to understand the rate and extent of adaptive radiation.     

Utilization of phosphate diester by the marine diatom Chaetoceros ceratosporus

Utilization of phosphate diester (PDE) and phosphodiesterase(PDEase) production by five marine phytoplankton species wereexamined in the laboratory to evaluate the contribution of PDEto the growth of phytoplankton. Among the five marine phytoplanktonspecies tested, only Chaetoceros ceratosporus was able to usethe PDE compound, bis(p-nitrophenyl) phosphate (bis-NPP), effectivelyas a sole phosphorus source. In addition, C. ceratosporus simultaneouslyproduced both PDEase and alkaline phosphatase (APase) at almostequal activity levels under the phosphate-deficient condition.These results suggest that PDE compounds presumably play animportant role as a phosphorus source for PDEase-producing phytoplanktonin coastal environments.     

一个1B/1R小麦-黑麦染色体易位的鉴定

本研究对冬小麦品系73(36)9-1的1B/1R易位染色体进行了遗传分析。发现73(36)9-1有一对随体染色体,它的两个亲本矮丰四号及洛夫林10(Lovrin lo)分别有两对和一对随体染色体。观察用矮丰四号回交的F_1,绝大部分花粉母细胞的中期染色体都能正常配对,而用洛夫林10回交的,除了多数产生两个单价体之外,正常配对的情况也能经常看到。同时还发现,73(36)9-1和“中国春”双端体(CSDT)的1BL能很好地配对并形成一个棒状的异形二价体,而它和CSDT 1BS的染色体则主要产生20″+1′+t′的构型,从而证明易位发生在1B染色体的短臂,并且该易位的片段来自黑麦染色体1RL。本文还讨论了该易位发生的可能途径,推断是由于在F_1花粉母细胞中的两个单价体(一个是小麦染色体1B,一个是黑麦染色体1R)同时进行错分裂之后产生的两种端着丝点染色体(1BL和1RL)重新并合形成的,因而冬小麦73(36)9-1可能是一个自发产生的易位系。     

Purified tyrosine kinases, the EGF receptor kinase and the src kinase, can catalyze the phosphorylation of the band 3 protein from human erythrocytes

The band 3 glycoprotein from human erythrocytes was found to be phosphorylated on tyrosine residues by the purified EGF receptor kinase and the purified src kinase in vitro. Kinetic analysis revealed that Km of the band 3 protein phosphorylation by the EGF receptor kinase was 0.17 microM and 0.65 microM in the absence and presence of EGF (3 X 10(-7)M), respectively, and that in the case of the src kinase it was 0.4 microM. From these data the band 3 protein can be regarded as one of the best substrates common for the EGF receptor kinase and the src kinase in vitro.     

Stimulative and inhibitory effects of bacteria on the growth of microalgae

Several examples of stimulative and inhibitoryeffects of bacteria on microalgal growth areintroduced, and the importance of bacteria in algalmass culture is investigated. Diatoms are often usedas live food for planktonic larvae of sea urchin andbivalves. Monodispersed Chaetoceros ceratosporum hasbeen cultivated by using clean, high nutrient content,deep seawater (DSW). However, the growth rate and cellyield of diatoms fluctuated, to relatively largeextent, with the season that DSW was collected. Whensome bacterial strains isolated from DSW were added tothe culture, diatom growth was often stimulated and arelatively constant cell yield was obtained. Anotherdiatom species, C. gracilis, was also stimulated byadding some bacterial strains to cultures. Thepositive effect of bacteria on diatoms was observednot only for planktonic species, but also on attachedspecies. A benthic diatom, Nitzschia sp., wasstimulated by a bacterial film of Alcaligenes on thesurface of the substratum. On the other hand, a strainof Flavobacterium sp. isolated from natural seawaterduring the decline period of an algal bloom had a strongalgicidal effect on the red tide plankton,Gymnodinium mikimotoi. Recent reports demonstratethat many bacterial strains have significantalgicidal effects on many species of red tideplankton. These results indicate that bacterialeffects should be taken into account to obtain stablemass culture of food microalgae.     

Continuous culture with deep seawater of a benthic food diatom Nitzschia sp.

A continuous culture system for a benthic food diatom Nitzschia sp. wasestablished by using properties of high nutrient and clean of deep seawater(DSW). DSW collected from 320 m depth in Muroto City, Japan, was introducedinto a glass-pipe bioreactor (14 cm length, 3 cm diam.) containing glassbeads of 0.5 cm diam. as substrata for the alga, and it was incubated at18°C · 80Em^–2sec^–1 · L:D=14:10. The chlorophyll a yield of benthicdiatoms in a reactor as a unit of surface area of the substratum was only0.001–0.003 g cm^–2 when the flow rate of DSW was 0(batch culture conditions). However, when DSW was supplied continuously to areactor, the yield increased to 1.4 g-chl.a cm^–2 alongwith the increase in flow rate of DSW. Moreover, amounts of chl.a washed outof the system were negligible, 0.0014 to 0.0045%, even though theflow rate of DSW was as much as 25 times h^–1, suggesting thatsloughing of benthic diatoms from the substratum was minimized. Although theyield of diatoms fluctuated significantly at the time that the DSW wascollected, the variation could be minimized by increasing the flow rate ofDSW. These results indicate that the continuous culturing system with DSWsupports the stable and effective mass culture of benthic food diatom.     

Occasional pathogenic bacteria promoting ice-ice disease in the carrageenan-producing red algae Kappaphycus alvarezii and Eucheuma denticulatum (Solieriaceae,Gigartinales, Rhodophyta)

The bacterial isolates from normal and diseased branches of Kappaphycus alvarezii and Eucheuma denticulatum in the Philippines were examined for possible role in the development of the ice-ice disease. The numbers of bacteria on and in ice-iced branches were 10–100 times greater than those from normal, healthy ones. Gram-positive bacteria predominated in almost all branch sources, but with an increasing proportion of agar-lysing bacteria in branches suffering from the ice-ice disease. These agar-lysing bacteria were composed of yellow and non-pigmented, spreading colonies identified to the Cytophaga-Flavobacterium complex and the Vibrio group. Among isolates which mainly appeared on ice-iced branches, two strains, designated as P11 (Vibrio sp.) and P25 (Cytophage sp.), which showed pathogenic activity, were obtained. These strains caused early ice-ice whitening of K. alvarezii especially when subjecting branches to environmental stress, such as reduced salinity and light intensity, suggesting that these bacteria were occasionally pathogenic. This paper offers new evidence of bacterial role in the development of so-called ice-ice disease among farmed species of Kappaphycus.     

Secretion, subcellular localization and metabolic status of inorganic pyrophosphate in human platelets. A major constituent of the amine-storing granules.

The platelet content of PPi is 1.90 +/- mumol/10(11) platelets (S.E.M., n = 19) or about 10.5 nmol/mg of protein, several hundred times that found for rat liver. Some 80% of this PPi is secreted by platelets treated with thrombin with a time course and dose-response relationship similar to secretion of ATP, ADP and 5-hydroxytryptamine (serotonin) from the platelet dense granules. During platelet aggregation induced by ADP and adrenaline, substantial amounts of PPi were secreted, but no release of acid hydrolases was observed. Subcellular-fractionation studies showed that the PPi is highly enriched in the same fraction that contains the storage organelles which store ATP, ADP, Ca2+ and 5-hydroxytryptamine. Inorganic pyrophosphatase was present mainly in the soluble fraction and in the mitochondria. Secretion studies done with platelets prelabelled with [32P]Pi showed that the sequestered PPi was relatively metabolically inactive, as is the ATP and ADP in the storage organelles. The possible participation of PPi in the formation of a bivalent-cation-nucleotide complex associated with amine storage is discussed.     

Immunoelectron microscopic study on interactions of noninfectious sendai virus and murine cells.

The early interactions of LLC-MK2 cell-grown noninfectious Sendai virus and a murine cell line, P815 mastocytoma ascitic cells, were studied by electron microscopy, using the ferritin-conjugated antibody technique with anti-virus glycoprotein serum. For comparison, the interactions of egg-grown infectious Sendai virus with the same cells were also examined. When noninfectious virus was adsorbed to the cells in the cold, the cell membranes become partially invaginated at the site of contact of adsorbed virions, but ferritin-conjugated antibodies did not penetrate into the areas of envelope-cell membrane association. This pattern of virus attachment was similar to that of infectious virus attachment. Upon subsequent incubation at 37 degrees C, most of the adsorbed noninfectious virions were taken into cytoplasmic vesicles and then degraded, although a few virions remained attached to the cell membrane. No evidence of fusion of envelopes of noninfectious virions was obtained. On the other hand, envelopes of infectious virions fused with the cell membrane, and the transferred viral antigens diffused on the cell surfaces and then decreased in number.     

Bacterial oxidation of polyethylene glycol.

The metabolism of polyethylene glycol (PEG) was investigated with a synergistic, mixed culture of Flavobacterium and Pseudomonas species, which are individually unable to utilize PEGs. The PEG dehydrogenase linked with 2,6-dichlorophenolindophenol was found in the particulate fraction of sonic extracts and catalyzed the formation of a 2,4-dinitrophenylhydrazine-positive compound, possibly an an aldehyde. The enzyme has a wide substrate specificity towards PEGs: from diethylene glycol to PEG 20,000 Km values for tetraethylene glycol (TEG), PEG 400, and PEG 6,000 were 11, 1.7, and 15 mM, respectively. The metabolic products formed from TEG by intact cells were isolated and identified by combined gas chromatography-mass spectrometry as triethylene glycol and TEG-monocarboxylic acid plus small amounts of TEG-dicarboxylic acid, diethylene glycol, and ethylene glycol. From these enzymatic and analytical data, the following metabolic pathway was proposed for PEG: HO(CH2CH2O)nCH2CH2OH leads to HO(CH2CH2O)nCH2CHO leads to HO(CH2CH2O)nCH2COOH leads to HO(CH2CH2O)n-1CH2CH2OH.