Competition of cyclooctenes and cyclooctadienes for ethylene binding and activity in plants

trans-Cyclooctene, cis,trans-1,5-cyclooctadiene, and cis,trans-1,3-cyclooctadiene have been compared with the cis and cis,cis isomers and with 2,5-norbornadiene for competition with ethylene for binding in mung bean sprouts and tobacco and for action (induction of chlorophyll degradation) in banana. The compounds containing a trans double bond were much more effective in competition for binding and action than the cis and cis,cis compounds. trans-Cyclooctene and cis,trans-1,3-cyclooctadiene were in the general range of 50–90 times more effective than 2,5-norbornadiene.R.J. Reynolds Research Apprentice     

Synaptic connections of the common inhibitory motoneurone within the fifth thoracic ganglion of crayfish

The common inhibitor (CI) has been studied morphologically and electrophysiologically in the fifth thoracic ganglion of crayfish (Procambarus clarkii). It has a large soma and possesses two separate dendritic fields arising from distinct integrative segments.In vitro preparations display motor outputs ranging from tonic activity to fictive locomotion. The CI's tonic firing frequency increases as more excitors are recruited, and displays two peaks of frequency during fictive locomotion, one during stance, the other during swing.Paired intracellular recordings have been used to demonstrate the different central synaptic connections received or made by the CI. At least 27% of the proximal excitors receive monosynaptic connections from the CI corresponding to post-synaptic depolarizations of small amplitude mediated by GABA. However as they do not change the overall activities of the excitors which receive them, they may be used for local inhibition within the dendrites. Besides, electrical synapses between several proximal excitors and the CI may synchronize their activity.The CI receives synaptic connections arising from interneurones. Some are direct either by inhibitory monosynaptic connections or by electrical couplings whereas others arise through polysynaptic pathways. All these connections are functionally significant in the control of the CI firing activity and in its motor coordinations.     

Induced diploid gynogenesis and polyploidy in the ornamental (koi) carp Cyprinus carpio L.

The results of a series of experiments conducted in our laboratory on the ornamental common carp (koi), aimed at optimizing heat-shock chromosome-set manipulation procedures, are described. The timing of heat-shock initiation was expressed in the relative unit of embryological age (₀) in order to standardize this parameter, the absolute time for heat-shock initiation being calculated from duration of one ₀ at two different pre-treatment water temperatures. Heat shocks were applied within the periods of 0.05–0.60 ₀ and 1.20–2.20 ₀ which, respectively, cover the successive phases of the 2nd meiotic division and the 1st cleavage. The highest production of diploid gynogenetic offspring was observed when heat shocks were initiated at 0.15–0.25 ₀ and at 1.5 ₀, after insemination, corresponding to anaphase of meiosis-II, and metaphase of the 1st cleavage, respectively. Similar results were obtained irrespective of the different pre-treatment water temperatures, thus confirming the possibility of standardizing heat-shock timing by ₀.     

Suppression of phaseolin and lectin in seeds of common bean, Phaseolus vulgaris L.: increased accumulation of 54 kDa polypeptides is not associated with higher seed methionine concentrations

Suppression of phaseolin and lectin accumulation in common bean resulted in higher concentrations of bean seed polypeptides with apparent molecular weights of 54 kDa and from 70 to 84 kDa on SDS-polyacrylamide gel electrophoresis. Polypeptides of 54 and 56 kDa segregated as products of different alleles. Genes for the 54/56 kDa bands and phaseolin were estimated to be 26.2±3.7 map units apart. The 54 kDa band phenotype manifested by SDS-PAGE consisted of from one to three polypeptides of 54 kDa MW on 2D gels, and the 56 kDa phenotype consisted of one polypeptide of 56 kDa plus two minor polypeptides of 54-54.5 kDa molecular weight. The pK_I of these polypeptides was approximately 5.25. The methionine content of the 54 kDa polypeptides of the cultivar Great Northern Star was 1.6±0.1 g/100 g protein, which was not statistically different from the value (1.5±0.1%) obtained for phaseolin isolated by the same procedure. F₂ seeds deficient for phaseolin and lectin contained as much total N per g as wild-type seeds and were not shrunken, but contained 50% more free amino acids. F₂ seeds from two of the three populations contained from 8 to 13% less methionine per mg total N.     

利用离体诱变技术选育小麦大粒种质的研究

以鲁麦１２等为材料进行幼层培养,转分化前辐照１０００ｒａｄ,在Ｒ２代调查千粒重变异情况,结果表明,后代千粒重发生了显著变化,变异范围为３９．５—６８．５ｇ．突变率高达６３．０８％,最高千粒重超过对照４０．９５％。已选出一批大粒材料应用于生产．其中核生二号新品种千粒重６５ｇ,杂交后代表明,大粒变异多为显性突变。     

A common allergenic epitope of Bermuda grass pollen shared by other grass pollens

The present study disclosed the cross-reactivity between Bermuda grass pollen (BGP) and other grass pollens using monoclonal antibodies (MAbs) and polyclonal antiserum. MAb 9–13, directed against a group of minor allergens of BGP (Cyn d Bd68K, 48K, 38K) was found to cross-react with extracts of ten other grass pollens. Immunoblotting assays illustrated that MAb 9–13 cross-reacted with multiple components of most of these pollens, and the major cross-reactive components had molecular weights of 29–36 kD. The cross-reactivity between BGP andLol pI, the group I allergen of rye grass pollen, was further evaluated;Lol pI was recognized by MAb 9–13, but not by our MAbs/polyclonal antiserum againstCyn dI, the major allergen of BGP. These results suggest that the epitope recognized by MAb 9–13 is a common (C) epitope shared byLol pI andCyn d Bd68K, 48K, 38K, andCyn dI does not share significant antigenicity withLol pI. In a modified radio-allergosorbent test, IgE antibodies in the serum of BGP-allergic patients reacted mildly with C-epitope-bearing components of both BGP and rye grass pollens, and this binding could be blocked specifically by MAb 9–13. This suggests that in addition to an antigenic cross-reaction, the C epitope can also lead to an allergenic cross-reaction.     

Amplified somatic embryogenesis from male flowers of triploid banana and plantain cultivars (Musa spp.)

Summary Somatic embryogenesis and plant regeneration of banana and plantain cultivars (Musa spp.) were obtained by culturing young male flowers. Multiplication and maintenance of embryogenic cultures were achieved by culturing somatic embryos in a temporary immersion system (SIT). A multiplication rate of 40 allowed us to obtain more than 6000 somatic embryos after 6 mo. of subculture. Plant recovery frequencies were 60 to 70%. This method was expanded to different banana and plantain genomic groups.     

草鱼、鲤、鲢、鳙和尼罗罗非鱼肝胰脏和肠道蛋白酶活性的初步探讨

草鱼、鲤、鲢、鳙肝胰脏和肠蛋白酶的最适pH值分别为8.7、8.7、7.6、7.6和8.4、8.7、8.0、8.4。草鱼、鲤和尼罗罗非鱼的肝胰脏蛋白酶活性比肠的高;鲢和鳙的肝胰脏蛋白酶的活性却比肠的低;尼罗罗非鱼胃的蛋白酶活性明显高于肝胰脏和肠的。草鱼、鲤和尼罗罗非鱼的肝胰脏蛋白酶活性明显高于鲢和鳙的;5种鱼的肠蛋白酶活性,鲤最高,尼罗罗非鱼最低,草鱼、鲢、鳙和尼罗罗非鱼间蛋白酶活性无明显差异。草鱼、鲤、鲢和尼罗罗非鱼的肠蛋白酶活性由前向后递减,而鳙的则以中肠活性最高。     

Observations on egg-laying behaviour of the banana weevil,Cosmopolites sordidus (Germar)

Banana weevil females laid on an average 2.7 eggs/week in rhizome material and 0.7 eggs/week in pseudostem material in the laboratory. At extremely high weevil population densities the egg-laying activity declined. Under controlled field conditions 0.7 eggs/week were laid in banana suckers and 1.3 eggs/week in stumps of harvested suckers. 25% of the weevil stages found in suckers in the field were eggs of which 78% were laid in the rhizome and 22% in the pseudostem base. The majority of eggs was deposited in the crown area of the rhizome followed by the remaining surface area of the rhizome, the walls of abandoned larval tunnels in rhizome and pseudostem and the leaf sheaths. 58% of the eggs found were considered accessible to egg predators.     

香蕉林土壤可培养放线菌分离、鉴定及其抑菌活性

【背景】香蕉枯萎病是香蕉的顽固性疾病,制约着香蕉产业的发展,因此,筛选出对香蕉枯萎病菌(尖孢镰刀菌古巴专化型4号生理小种,简称Foc4)具有抑制活性的生防菌株具有重要意义。【目的】分离香蕉林土壤样品中放线菌并进行物种的初步鉴定,测定其对包括香蕉枯萎病致病菌的7种病原菌的拮抗活性,获得高活性菌株,以获得解决香蕉枯萎病的生物防治策略。【方法】采集多份广西地区香蕉林土壤样品,采用超声波等手段对其预处理,设置多种特异性培养基从中分离放线菌资源,对获得的放线菌进行基于16SrRNA基因序列的物种鉴定,以7种病原菌为靶标,采用平板对峙法从中筛选抑菌活性菌株,最后采用菌丝生长速率法对Foc4的抑菌率进行测定。【结果】从香蕉林土壤中分离出138株放线菌均为链霉菌,其中5株为潜在新种,分别为X1085、X1052、X2052、X3059和X4046;筛选出具有抑菌活性的菌株77株,阳性率为55.8%。20株对Foc4具有抑制活性,其中4株拮抗效果明显,抑制率大于80%,菌株X4050的抑菌率高达93.76%。【结论】初步明确了香蕉林土壤中可培养放线菌的物种信息,其中部分放线菌为未知物种,活性分析显示一半...