西藏浪错兰格湖裸鲤种群繁殖生物学特征

2017年7月至2018年6月,于西藏自治区昂仁县浪错采集兰格湖裸鲤(Gymnocypris chui)307尾,开展种群繁殖生物学研究。结果显示,浪错兰格湖裸鲤在3～5月性成熟系数较高。雌性最小性成熟个体年龄为7龄,体长217mm,体重122.68g,成熟系数为3.92%;雄性最小性成熟个体年龄为6龄,体长198 mm,体重91.93 g,成熟系数为3.34%。其平均成熟卵径为2.18 mm,卵径分布为单峰型。绝对繁殖力为862～8 933粒/尾,平均绝对繁殖力为(2 885±2 765)粒,相对繁殖力为7～43粒/g,平均相对繁殖力为(15±11)粒/g。绝对繁殖力与体长和体重呈显著正相关,相对繁殖力与体长、体重的相关性不显著。繁殖群体性比(♀︰♂)为1︰0.967,符合1︰1比例。     

张氏(餐)的繁殖生物学特性

文章对赤水河河口段张氏(餐)的繁殖生物学进行了研究.结果表明:5-9月份为其繁殖期;最小性成熟个体为雌性体长77mm,体重5.3g;雄性体长108mm,体重9.4g,均为1龄;繁殖群体性比为1.07:1,由4个年龄组组成,其中2龄个体占绝对优势.性成熟系数3-7月份逐渐增大,然后持续减小,至12月降到全年最小值.卵径(0.75±0.14)mm呈单峰型,绝对繁殖力(11010±7723)粒,相对繁殖力(275.1±138.4)粒/g,每克卵巢卵粒数(3789±1389)粒.该种为单批产卵类型鱼类.绝对繁殖力随着鱼体体长、体重和年龄的增长而增大.     

长江宜昌段鲢的繁殖生物学特征

2014年3月至2016年9月在长江中下游宜昌江段共收集鲢(Hypophthalmichthys molitrix)样本433尾,进行繁殖生物学研究。该江段鲢的繁殖时间为每年的5月下旬至8月上旬,以6~7月为盛产期。繁殖群体体长310~927 mm,体重600~17 090 g,由3~7龄共5个年龄组组成,3龄群体数量上占绝对优势,占繁殖群体的45.2%。雌雄性比为1.43︰1,雌雄群体间体长-体重关系存在显著性差异(0.01P0.05)。采用Logistic方程推算出初次性成熟雌性个体体长为482.3 mm,体重为2 206.7 g;初次性成熟雄性个体体长为484.0 mm,体重1 677.5 g。卵径(1.01±0.12)mm,大小分布呈单峰型,为单批产卵型鱼类。绝对繁殖力(477 662±9 631)粒,相对繁殖力为(93.38±5.92)粒/g,绝对繁殖力随着鱼体长、体重增长而增大。与其他地理种群相比较,宜昌江段鲢总体表现为卵径相对较小而繁殖力较大。     

塔里木河叶尔羌高原鳅繁殖生物学研究

2010年7月至2011年12月,在塔里木河阿拉尔段采集叶尔羌高原鳅Triplophysa (Hedinichthys) yar-kandensis (Day)940尾(除性别未辨个体外)用于繁殖生物学研究。种群雌雄比为0.85︰1,最小性成熟,雌性个体体长为8.2 cm,体重为7.4 g,年龄为3龄;雄性个体体长为6.5 cm,体重为3.4 g,年龄为2龄。叶尔羌高原鳅卵径分布呈单峰形,推测应属于同步产卵类型。计算了88尾Ⅳ-Ⅴ期雌鱼的怀卵量,其体长范围30-195 mm,体重范围3.59-114.04 g,绝对繁殖力为1101-56320(9944±5487)粒,相对繁殖力为824-1140(982±158);塔里木河阿拉尔段叶尔羌高原鳅种群繁殖力(Fp)为403.46万粒。     

锦江翘嘴鲌的繁殖生物学特征

对2015年1月至12月采集于锦江的翘嘴鲌(Culter alburnus)进行了繁殖生物学特征的研究。锦江的翘嘴鲌繁殖期集中在6~7月,属分批产卵类型。繁殖群体年龄在3+龄至6+龄之间,体长250~537 mm,体重184.9~2 587.5 g。雌雄性比1.14︰1,体表差异表现在泄殖孔和腹部膨胀程度,雌雄群体间体长-体重关系存在显著性差异(0.01P0.05)。性成熟雌鱼绝对繁殖力25 067~54 274粒,相对繁殖力24.2~36.9粒/g,平均卵径(1.1±0.3)mm。性成熟系数在1~5月份逐渐增大,6月明显上升,7月达到最高峰,8月显著下降,9~12月逐渐趋于平缓。采用Logistic方程推算了初次性成熟个体特征,雄性体长273 mm,体重192.0 g,年龄3.4龄;雌性体长311 mm,体重249.4 g,年龄4.2龄。锦江种群繁殖期与其他地理种群相近,但绝对繁殖力和相对繁殖力明显偏小。     

山美水库两种入侵罗非鱼繁殖生物学比较

为比较山美水库两种入侵齐氏罗非鱼(Coptodon zillii)和伽利略罗非鱼(Sarotherodon galilaeus)种群的繁殖生物学特征,于2021年3—10月份在山美水库逐月采样,分析了繁殖时间、性比、绝对繁殖力、相对繁殖力和成熟卵径等特征。结果表明,两种罗非鱼均于4月份开始繁殖,齐氏罗非鱼繁殖高峰为7月, 10月结束繁殖;伽利略罗非鱼繁殖高峰为6月, 9月结束繁殖。齐氏罗非鱼平均绝对繁殖力为(4009.85±1305.69)粒、平均体重相对繁殖力为(67.32±15.63)粒/g、平均体长相对繁殖力为(31.31±5.03)粒/mm;伽利略罗非鱼平均绝对繁殖力为(1701.85±591.29)粒、平均体重相对繁殖力为(6.46±0.87)粒/g、平均体长相对繁殖力为(8.22±2.33)粒/mm;齐氏罗非鱼的绝对繁殖力、体重相对繁殖力和体长相对繁殖力均显著高于伽利略罗非鱼,平均成熟卵径则显著小于伽利略罗非鱼。齐氏罗非鱼和伽利略罗非鱼繁殖群体的雌雄性比分别为1.59和1.83,两个种群的雌雄性比无显著差异,但均显著偏离1﹕1。研究表明两种共同入侵的罗非鱼种群具有不同的繁殖...     

金沙江攀枝花江段白缘(鱼央)的繁殖生物学

为丰富白缘(鱼央)Liobagrus marginatus(Günther)的基础生物学资料,于金沙江攀枝花江段收集到729尾性腺可辨的样本,分析其年龄结构、性别比、初次性成熟个体大小以及繁殖力等繁殖生物学特征。结果表明:繁殖群体由1~4龄4个年龄组组成,其中2龄个体在数量上占绝对优势(63.83%),其对种群繁殖力的贡献为62.07%。在性成熟个体中,雌性和雄性分别为64尾和77尾,雌雄比=1∶1.20;符合1∶1理论比值(χ~2=1.199,P0.05);雌、雄最小性成熟个体体长分别为66.80 mm、67.32 mm,体质量分别为5.7 g、6.7 g。攀枝花江段白缘(鱼央)的繁殖季节为3—6月,绝对繁殖力平均值为161.2粒±55.1粒。Ⅳ期卵巢中卵子发育不完全同步,卵径变幅为0.29~3.86 mm。金沙江攀枝花江段白缘性成熟快,但繁殖力低,繁殖群体主要由低龄个体组成,种群资源亟需保护。     

雅鲁藏布江黑斑原鮡繁殖生物学研究

对2004-2006年采集于雅鲁藏布江拉萨河的190尾黑斑原鮡进行了繁殖生物学研究。雄性最小性成熟(精巢Ⅳ期)个体体长141.7mm,体重45.2g,性体指数1.09%,雌性最小性成熟(卵巢Ⅳ期)个体体长146.8mm,体重66.7g性体指数11.52%,相应年龄均为5龄。初次性成熟年龄(L50):♂,170.1mm相应年龄为7龄;♀,150.2mm,相应年龄5龄。通过组织切片法和GSI的周年变化分析,繁殖时间集中在5-6月,每年繁殖一次,繁殖之后的6-8月卵巢从Ⅵ期回复到Ⅲ期,9月卵巢发育到Ⅳ期越冬。卵径频率分布显示,卵巢发育类型为分批同步型,卵巢中至少存在2批卵径,每年成熟一批卵并同时产出,产卵类型为完全同步产卵。卵黏性,成熟卵卵径在2.04-3.37mm之间,平均(2.83±0.16)mm。对19尾产卵前夕(体长为151.0-210.0mm)的标本进行统计,其绝对繁殖力范围在525-2058粒之间,平均为(1244±346)粒,相对繁殖力为(14.7±5.8)粒/g。绝对繁殖力与体长呈直线正相关,表达式为F=13.624L-1187。       

华南地区外来鱼类革胡子鲶的繁殖生物学

2011年8月—2015年8月在华南地区主要河流收集255尾革胡子鲶(Clarias gariepinus)样本,对其繁殖生物学特征进行研究。结果表明:革胡子鲶繁殖季节为5—8月,繁殖旺季为6—7月,卵径分布呈现明显的多峰型;成熟系数与脂肪系数和肥满度的周年变化存在相反的趋势;绝对繁殖力为2850~605720粒,均值234232±175498粒,与体长、体重和年龄呈正相关;相对繁殖力为20~445粒·g~(-1),均值165±99粒·g~(-1),随体长、体重和年龄的增加呈先增加后趋于稳定趋势;绝对繁殖力和相对繁殖力均大于常见的鲶科鱼类。繁殖群体性比为1∶1.12,符合1∶1比例;雌、雄鱼最小性成熟个体均为1龄,Ⅳ期性腺;雌鱼体长174 mm,体重119.5 g,成熟系数为8.50%;雄鱼体长205 mm,体重116.2 g,成熟系数为0.45%;繁殖群体以1和2龄鱼为主,分别占繁殖群体总数的42.28%和51.68%,以补充群体占优势;华南地区革胡子鲶野生种群具有分批产卵、相对繁殖力高、卵径小、性成熟年龄低的特征,有利于其迅速建立稳定的种群,应加强对革胡子鲶野生种群动态的监测力度,并进一步采取防控措施。     

厚颌鲂(Megalobrama pellegrini)的繁殖生物学特征

从长江上游一级支流龙溪河收集了1382尾厚颌鲂开展繁殖生物学研究。结果表明,厚颌鲂繁殖期为4～7月份,盛期为4～5月份,在繁殖季节可借第二性征辨别性别。繁殖群体主要由2、3龄个体组成,总性比♀∶♂＝1∶1.83。厚颌鲂2龄初次性成熟（♀∶75%;♂∶94.7%）,3龄个体全部成熟。最小性成熟雌性全长189.0mm,体长158.0mm,体重72.1g,成熟系数2.7%;雄性全长179.0mm,体长149.0mm,体重57.1g,成熟系数2.2%。厚颌鲂绝对怀卵量为(59587.22±59018)粒,相对怀卵量为(212.64±89.50)粒/g或(230.96±137.63)粒/mm,绝对怀卵量和相对怀卵量均在5龄大幅增长。比较繁殖力以3龄组最高,2、4、5龄组相近。集群繁殖需要18℃以上水温和其他一些生态因子刺激,亲鱼追逐约1h左右产卵。     

Collagen-like triple helix formation of synthetic (Pro-Pro-Gly)10 analogues: (4(S)-hydroxyprolyl-4(R)-hydroxyprolyl-Gly)10, (4(R)-hydroxyprolyl-4(R)-hydroxyprolyl-Gly)10 and (4(S)-fluoroprolyl-4(R)-fluoroprolyl-Gly)10.

For the rational design of a stable collagen triple helix according to the conventional rule that the pyrrolidine puckerings of Pro, 4-hydroxyproline (Hyp) and 4-fluoroproline (fPro) should be down at the X-position and up at the Y-position in the X-Y-Gly repeated sequence for enhancing the triple helix propensities of collagen model peptides, a series of peptides were prepared in which X- and Y-positions were altogether occupied by Hyp(R), Hyp(S), fPro(R) or fPro(S). Contrary to our presumption that inducing the X-Y residues to adopt a down-up conformation would result in an increase in the thermal stability of peptides, the triple helices of (Hyp(S)-Hyp(R)-Gly)(10) and (fPro(S)-fPro(R)-Gly)(10) were less stable than those of (Pro-Hyp(R)-Gly)(10) and (Pro-fPro(R)-Gly)(10), respectively. As reported by B?chinger's and Zagari's groups, (Hyp(R)-Hyp(R)-Gly)(10) which could have an up-up conformation unfavorable for the triple helix, formed a triple helix that has a high thermal stability close to that of (Pro-Hyp(R)-Gly)(10). These results clearly show that the empirical rule based on the conformational preference of pyrrolidine ring at each of X and Y residues should not be regarded as still valid, at least for predicting the stability of collagen models in which both X and Y residues have electronegative groups at the 4-position.     

Synthesis and luminescence properties of a blue-emitting Sr(3.5) Y(6.5) O(2) (PO(4) )(1.5) (SiO(4) )(4.5) :Eu(2+) phosphor

A novel blue‐emitting Sr_3.5Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5:Eu²⁺ phosphor was synthesized via a solid‐state reaction. Powder X‐ray diffraction (XRD) analysis demonstrated that the Sr_3.5Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5 host had a hexagonal crystal structure in the space group P6₃/m and unit cell parameters a = 9.418 Å, c = 6.900 Å. The as‐prepared phosphor showed a blue emission and all the main emission peaks were located at around 466 nm for different excitation wavelengths of 297, 333 and 391 nm. The temperature dependence of the photoluminescence property was investigated in the range 20–250 °C, and the emission intensity decreased to 71% of the initial value at room temperature on increasing the temperature to 150 °C. According to the classical theory of fluorescent thermal quenching, the activation energy (ΔE) for the thermal quenching luminescence of the as‐prepared Sr_3.45Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5:0.05Eu²⁺ phosphor was determined to be 0.20 eV. Copyright © 2011 John Wiley & Sons, Ltd.     

Role of tfdC(I)D(I)E(I)F(I) and tfdD(II)C(II)E(II)F(II) gene modules in catabolism of 3-chlorobenzoate by Ralstonia eutropha JMP134(pJP4)

The enzymes chlorocatechol-1,2-dioxygenase, chloromuconate cycloisomerase, dienelactone hydrolase, and maleylacetate reductase allow Ralstonia eutropha JMP134(pJP4) to degrade chlorocatechols formed during growth in 2,4-dichlorophenoxyacetate or 3-chlorobenzoate (3-CB). There are two gene modules located in plasmid pJP4, tfdC(I)D(I)E(I)F(I) (module I) and tfdD(II)C(II)E(II)F(II) (module II), putatively encoding these enzymes. To assess the role of both tfd modules in the degradation of chloroaromatics, each module was cloned into the medium-copy-number plasmid vector pBBR1MCS-2 under the control of the tfdR regulatory gene. These constructs were introduced into R. eutropha JMP222 (a JMP134 derivative lacking pJP4) and Pseudomonas putida KT2442, two strains able to transform 3-CB into chlorocatechols. Specific activities in cell extracts of chlorocatechol-1,2-dioxygenase (tfdC), chloromuconate cycloisomerase (tfdD), and dienelactone hydrolase (tfdE) were 2 to 50 times higher for microorganisms containing module I compared to those containing module II. In contrast, a significantly (50-fold) higher activity of maleylacetate reductase (tfdF) was observed in cell extracts of microorganisms containing module II compared to module I. The R. eutropha JMP222 derivative containing tfdR-tfdC(I)D(I)E(I)F(I) grew four times faster in liquid cultures with 3-CB as a sole carbon and energy source than in cultures containing tfdR-tfdD(II)C(II)E(II)F(II). In the case of P. putida KT2442, only the derivative containing module I was able to grow in liquid cultures of 3-CB. These results indicate that efficient degradation of 3-CB by R. eutropha JMP134(pJP4) requires the two tfd modules such that TfdCDE is likely supplied primarily by module I, while TfdF is likely supplied by module II.     

Induction of in vitro flowering in Dendrobium Madame Thong-In (Orchidaceae) seedlings is associated with increase in endogenous N(6)-(Delta (2)-isopentenyl)-adenine (iP) and N (6)-(Delta (2)-isopentenyl)-adenosine (iPA) levels

We analysed the endogenous cytokinin levels of Dendrobium Madame Thong-In seedlings grown in vitro during vegetative and flowering-inductive periods. HPLC was used to fractionate the extracts and radioimmunoassay (RIA) was used for assay of zeatin (Z), dihydrozeatin (DZ), N(6)-(Delta(2)-isopentenyl)-adenine (iP) and their derivatives. Coconut water used in experiments was found to contain high level (>136 pmol ml(-1)) of zeatin riboside (ZR). Protocorms and seedlings cultured in medium with coconut water were found to contain 0.5-3.9 pmol g(-1) FW of the cytokinins analysed. Seedlings (1.0-1.5 cm) cultured in flowering-inductive liquid medium containing 6-benzyladenine (BA, 4.4 muM) and coconut water (CW, 15%) contained up to 200 and 133 pmol g(-1) FW of iP and iPA, respectively. These levels were significantly higher than all other cytokinins analysed in seedlings of the same stage and were about 80- to 150-folds higher than seedlings cultured in non-inductive medium. During the transitional (vegetative to reproductive) stage, the endogenous levels of iP (178 pmol g(-1) FW) and iPA (63 pmol g(-1) FW) were also significantly higher than cytokinins in the zeatine (Z) and dihydrozeatin (DZ) families in the same seedlings. Seedlings that grew on inductive medium but remained vegetative contained lower levels of iPA. The importance of the profiles of iP and its derivatives in induction of in vitro flowering of D. Madame Thong-In is discussed.     

The helix-coil transitions of poly (dA)-poly (dT) and poly (dA-dT)-poly (dA-dT)

Helix–coil transition curves are calculated for poly (dA) poly(dT) and poly (dA-dT) poly (dA-dT) using the integral equation approach of Goel and Montroll.⁵ The transitions are described by the loop entropy model with the exponent of the loop entropy factor, k, remaining an arbitrary constant. The theoretical calculations are compared with experimental transition curves of the two polymers. Results indicate that the stacking energies for these two polymers differ by about 1 kcal/mole of base pairs. Also, a fit between theory and experiment was not possible for k > 1.70.     

Biology of Bactrocera (Zeugodacus) tau (Walker) (Diptera: Tephritidae)

The biology of the fruit fly Bactrocera tau, an important horticultural pest, was studied under laboratory conditions at 25°C and 60–70% relative humidity on Cucurbita maxima. The duration of mating averaged 408.03 ± 235.93 min. After mating, the female fly had a preoviposition period of 11.7 ± 4.49 days. The oviposition rate was 9.9 ± 8.50 eggs and fecundity was 464.6 ± 67.98 eggs/female. Eggs were elliptical, smooth and shiny white, turning darker as hatching approached, and measured 1.30 ± 0.07 mm × 0.24 ± 0.04 mm. The chorion has polygonal microsculpturing and is species-specific with polygonal walls. The egg period lasts for 1.3 ± 0.41 days. The duration of the larval period is 1.2 ± 0.42, 1.7 ± 0.48 and 4.0 ± 0.94 days for first, second and third instars, respectively. Pupation occurs in the sand or soil and pupal periods are 7.0 ± 0.47 days. The life cycle from egg to adult was completed in 14.2 ± 1.69 days; the longevity of mated females and males was 130.33 ± 14.18 and 104.66 ± 31.21 days, respectively. At least two to three generations were observed from June 2008 to June 2009.     

Spectroscopic investigations of Er(3+) :CdO-Bi(2) O(3) -B(2) O(3) glasses

This article reports on the optical properties of Er³⁺ ions doped CdO–Bi₂O₃–B₂O₃ (CdBiB) glasses. The materials were characterized by optical absorption and emission spectra. By using Judd–Ofelt theory, the intensity parameters Ω_λ (λ = 2, 4, 6) and also oscillatory strengths were calculated from the absorption spectra. The results were used to compute the radiative properties of Er³⁺:CdBiB glasses. The concentration quenching and energy transfer from Yb³⁺–Er³⁺ were explained. The stimulated emission cross‐section, full width at half maximum (FWHM) and FWHM × values are also calculated for all the Er³⁺:CdBiB glasses. Copyright © 2011 John Wiley & Sons, Ltd.     

Cationic (tripyrrinato)palladium(II) complexes

The formation of cationic palladium(II)complexes [TrpyPd^II]⁺X⁻ by salt metathesis of the respective trifluoroacetates with different salts of weakly coordinating anions X⁻ was investigated. With non-hydrolizable counterions, cationic mono- and dinuclear complexes are observed depending on the nature of the anion X⁻ and the solvent. The mononuclear cations, which are only formed with X = BAr^F, most probably carry a weakly bound molecule of dichloromethane at the fourth coordination site of Pd^II. When treated with diazoalkanes, only these are sufficiently reactive to form carbene complexes. Four- and five coordinate Lewis base adducts [TrpyPd^IIL]⁺ with L = CH₃NC, tBuNH₂, PMe₃, PEt₃ and PiPr₃ and [TrpyPd^IIL₂]⁺ with L = PMe₃ were prepared from the mononuclear cations [TrpyPd^II]⁺BAr^F−. From structural studies it becomes apparent, that the formation of stable five coordinate Pd^II species is restricted to medium size ligands and depends on the delicate balance between the steric influence of L and the strain, which is induced on the TrpyPd^II unit.