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1.
Relationships between male size, number, and weight of newborn were determined in the seaweed pipefish, Syngnathus schlegeli, with paternal care of embryos in the brood pouch. While the number of newborn increased linearly with the increase in male size, the pouch volume increased exponentially with the male size. This resulted in embryo density in the pouch negatively correlating with the male size. Newborn dry weight was negatively correlated with the embryo density in the pouch. Thus, larger males were considered to brood embryos at lower densities and give birth to heavier newborn. Neither paternal size nor embryo density seemed to have an effect upon developmental stage and total length of the newborn. Substantial weight loss of embryos during incubation indicated that paternal nutritional contribution to embryos is insignificant; therefore, the tendency of larger males to produce heavier newborn may not relate to allocation of paternal nourishment. Because egg weight increased with the female size, larger males are considered to receive the eggs of larger females and give birth to heavier newborn that developed from heavier eggs. Lower embryo density in larger males is attributable to the larger size of the heavier eggs. Assuming the pouch to be a cylindrical tube and the egg to be a sphere, geometrical calculations revealed that the relationship between the volumetric fraction of the pouch used by eggs (i.e. functional volume) and the male size was negatively quadric and had a peak. Increase in egg diameter increased the male size at which the functional volume of the pouch is maximized. Thus it appears that the size relationship of mates in pipefish is related to effective use of the pouch space.  相似文献   

2.
Summary Eggs of the carabid beetle Pterostichus oblongopunctatus kept under optimum conditions in petri dishes had a mean mortality of 8% (n=200), while the mortality of eggs incubated in fresh litter was 83% (n=250). Heating the litter up to 70° C and thus eliminating other organisms from the litter fauna reduced mortality to 18% (n=250). When eggs were deposited by the females themselves in a perspex cylinder containing an undisturbed soil sample, the mean egg mortality was 70% (n235), but when predators had been eliminated the mortality was only 7% (n235). The assumption of Grüm (1975) that egg mortality can be neglected does not hold for P. oblongopunctatus. The predators of the eggs must be common species, but it is not yet known to which family they belong.  相似文献   

3.
A method is described whereby arrays of samples ofClupea pallasi eggs may be stored during their preparation. The high fertilization potential retained by the eggs during short-term storage allows them to be fertilized synchronously when sample preparation is complete. A variation of the dry method of storage retained maximum fertilization potential (80–85%) of the eggs for about 1 hr, and of milt dilution (18 with 17 S sea water), about 7 hr. Following dry storage, eggs fertilized in salinities of 0–45 showed maximum rates of fertilization in salinities of 10–20, and fertilization rates 50% in salinities of 4.5–42. Salinities of fertilization influenced egg diameter, median hatching time, and larval length at hatching in egg samples transferred 21/2 hr after fertilization to an incubation salinity of 17 at 7°C. Fertilization rates were higher (90–95%) for eggs stored in 17 S at 7°C prior to fertilization. Under such wet storage conditions, maximum fertilization pontential was retained for about 2 hr. Highest fertilization rates (95–96%) were obtained for eggs stored and fertilized in salinities of 12–15. For the species and the area of origin considered (British Columbia), wet storage of eggs should result in maximum fertilization when the eggs are stored at 4°C for a period not greater than 2 hr prior to fertilization in the 12–15 S storage medium.Prepared under the auspices of the Canadian-German Scientific and Technical Cooperation Agreement.  相似文献   

4.
Mutagenic effectiveness and efficiency of EMS,DES and gamma-rays in rice   总被引:1,自引:0,他引:1  
Summary Data on chlorophyll mutation frequency after treatment with EMS, DES and gamma-rays and sequential administration of gamma-rays and the two alkylating agents in three varieties of rice have been used to work out quantitatively the effectiveness and efficiency of each mutagen and combination treatment. For effectiveness, the order is EMS > DES and for efficiency it is EMS > DES > gamma-rays. In some sequential treatments (Gamma-rays + DES in IR8 and Basmati; DES + gamma-rays in IR8 and Jhona; Gamma-rays + EMS in IR8 and Basmati; and EMS + gamma-rays in IR8, Jhona and Basmati) mutation frequency is more than additive (synergistic) but these treatments are decisively less efficient because of their relatively high injurious effects in the M1. generation. EMS induces more albinas than gamma-rays do. The mutational spectrum patterns induced by gamma-rays and DES are alike. In general, combination treatments tend to increase the frequency of albinas over other types of chlorophyll mutants.  相似文献   

5.
Life-history characteristics of the double-ended pipefish, Syngnathoides biaculeatus (Bloch), were investigated to determine growth rate, degree of sexual dimorphism, size at maturity, and reproductive biology. Growth rates of wild juveniles and adults calculated from monthly progression of length-frequency modes ranged from 0.8mmd–1 (fish lengths 120–145mm standard length (SL)) in summer to 0.2mmd–1 in winter (185–200mm SL). Growth of laboratory-reared juveniles up to 63d old was greater, ranging from 0.8 to 2.3mmd-1. The von Bertalanffy growth constant K was estimated at 0.0076d- 1, or 2.8year–1. Morphological differentiation between the sexes based upon abdominal pattern was possible for fish larger than 120mm SL, with females possessing a zigzag pattern on the abdomen. The association between this pattern and sex was confirmed by histological gonad analysis. Males were significantly longer than females during four of seven seasons examined, and a 1:1 sex ratio was determined for all seasons except autumn when the ratio was female biased. The breeding season was marked by the appearance of pregnant males between October and April, and during courtship both species exhibited increased pigmentation. The minimum paternal size at maturity was 185mm, the maximum length recorded 260mm. Clutch size ranged between 60 and 200 eggs, with a mean of 153. Ovaries had a sequential pattern of egg development, resulting in egg batches that approximated the number of eggs carried by brooding males. Additionally, all eggs in a brood were at the same developmental stage. This suggests that one female provides all of the eggs for one male per breeding event in a monogamous mating system.  相似文献   

6.
On age morphological changes of males of Chydoridae (Cladocera)   总被引:2,自引:2,他引:0  
N. N. Smirnov 《Hydrobiologia》1967,30(3-4):555-571
Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.  相似文献   

7.
The generation time ofP. branickii was studied using larval samples in conjunction with rearing experiments and continuous collection of egg masses across one year. This species produced three generations per year in a central German stream (280 m a.s.l., 50° 40 N). Its generation time was variable and obviously influenced by the photoperiod to which eggs and larvulae were subjected. It is thus concluded that two strains ofP. branickii were present in a single population, one bivoltine and the other trivoltine.  相似文献   

8.
This study examines various optimization criteria as potential sources of constraints that eliminate (or at least reduce the degree of) mechanical redundancy in prehension. A model of nonvertical grasping mimicking the experimental conditions of Pataky et al. (current issue) was developed and numerically optimized. Several cost functions compared well with experimental data including energylike functions, entropylike functions, and a motor command function. A tissue deformation function failed to predict finger forces. In the prehension literature, the safety margin (SM) measure has been used to describe grasp quality. We demonstrate here that the SM is an inappropriate measure for nonvertical grasps. We introduce a new measure, the generalized safety margin (GSM), which reduces to the SM for vertical and two-digit grasps. It was found that a close-to-constant GSM accounts for many of the finger force patterns that are observed when grasping an object oriented arbitrarily with respect to the gravity field. It was hypothesized that, when determining finger forces, the CNS assumes that a grasped object is more slippery than it actually is. An operative friction coefficient of approximately 30\% of the actual coefficient accounted for the offset between experimental and optimized data. The data suggest that the CNS utilizes an optimization strategy when coordinating finger forces during grasping.  相似文献   

9.
Two particular types of sialoglycoproteins have been detected in fish: polysialoglycoproteins containing 28-linked polysialic acid (8Neu5Gc2) n present in unfertilized Salmonidae fish eggs, and glycoproteins bearing oligo/polymers of deaminated neuraminic acids (KDN) found in the vitelline envelope of the eggs and ovarian fluid. We report the preparation and characterization of a monoclonal antibody specifically recognizing oligo/polymers of KDN sequences in glycoproteins and its application in immunohistochemistry. Fusion of spleen cells from a BALB/c mouse immunized with a KDN-rich glycoprotein (KDN-gp) containing (8KDN2) n 6(KDN23Gal13GlNAc13) GalNAc1 residues, with mouse myeloma cells yielded a hybrid cell line producing a monoclonal antibody that bound to KDN-gp, but not to KDN-gp depleted of KDN residues. The specificity of the monoclonal antibody, designated mAb.kdn8kdn, was determined by an enzyme-linked immunosorbent assay using KDN-gp samples that varied in KDN content. These antigens were prepared by the selective removal of KDN residues from the native KDN-gp. The mAb.kdn8kdn reacted most strongly with the intact KDN-gp and less strongly with KDN-gp samples containing decreased numbers of KDN residues. The mAb.kdn8kdn was shown specifically to recognize the 28-linked oligo/polyKDN sequences, (8KDN2) n , and to be able to distinguish specifically (8KDN2) n chains from (8Neu5Ac2) n and (8Neu5Gc2) n chains. The antibody was used successfully for the immunohistochemical detection of reactive KDN epitopes in sections of paraffin embedded rat pancreas. Several controls verified the specificity of the immunohistochemical staining, thus providing the first demonstration of (8KDN2) n sequences in a mammalian tissue. The mAb.kdn8kdn can now be used to search further for glycoconjugates containing (8KDN2) n chains and will facilitate studies on their biosynthesis, intracellular localization and function.  相似文献   

10.
Adenosine-5-triphosphate was synthesized by the phosphorylation of adenosine-5-diphosphate in aqueous solution containing cyanate as a condensing reagent and insoluble calcium phosphate produced from phosphate and calcium chloride. In a similar manner, adenosine-5-diphosphate was synthesized from adenosine-5-monophosphate. When the experiment was carried out in the conditions of 4 °C and pH 5.75, the formation of adenosine-5-diphosphate and adenosine-5-triphosphate from adenosine-5-monophosphate was observed in the yields of 19 and 7%, respectively. The other nucleoside-5-triphosphates were also produced from their respective diphosphates.  相似文献   

11.
Sedimentation equilibrium and low-angle laser-light scattering were used to determine the molar mass of the glycoprotein moieties in the complexes of sodium dodecyl sulphate with the human platelet membrane glycoproteins IIb (GPIIb), IIIa (GPIIIa), and the (GPIIb) and (GPIIb) subunits of GPIIb. The values obtained by both procedures, except those for GPIIb, agree within experimental error with those calculated from their chemical composition: GPIIb (114,000 g mol-1), GPIIb (22,200 g mol-1), and GPIIIa (91,500 g mol-1). The molar mass of GPIIb determined by light scattering (142,000 g mol-1) and sedimentation equilibrium at different solvent densities (134,000 g mol-1) also agree, within experimental error, with the values calculated either from its chemical composition (136,500 g mol-1) or from the sum of the molar masses of its subunits. However the molar mass determined by sedimentation equilibrium at constant solvent density, is consistently underestimated (116,000 g mol-1).High-performance size-exclusion chromatography in sodium dodecyl sulphate solutions overestimates the molar mass of these glycoproteins and their Stokes radii, and therefore the maximal frictional ratios derived from them.Abbreviations GPIIb glycoprotein IIb - GPIIIa glycoprotein IIIa - GPIIb and GPIIb and subunits of GPIIb, respectively - CM-GPIIb CM-GPIIb, and CM-GPIIIa, totally reduced and carboxymethylated forms of GPIIb, GPIIb, and GPIIIa, respectively - SDS sodium dodecyl sulphate - eosin-ITC eosin-5-isothiocyanate  相似文献   

12.
Summary The egg and central cells of Plumbago zeylanica have an average volume of 543,000 m3 and 2,560,000 m3 respectively, with surface areas of 38,600 m2 and 154,000 m2. The egg contains an average of 39,900 mitochondria and 730 plastids. The majority of the plastids are perinuclear (> 60%) with less than 40% in lateral areas or near the filiform apparatus. After fertilization, the number of maternal organelles exceeds paternal organelles by a ratio of 11,000 for mitochondria and 154 for plastids. The central cell contains an average of 178,700 mitochondria and 1,840 plastids. After fertilization, these organelles far exceed the number of sperm organelles transmitted, by a ratio of approx. 14,000 for plastids and 1820 for mitochondria. Biparental inheritance of plastids in the embryo is possible, but not favored; the only comparable data in Oenothera and Impatiens reveals that biparental inheritance is possible in up to 124 ratios. Plants lacking biparental plastid inheritance do not contain plastids in the sperm, and thus the presence of even few sperm plastids may result in expression. The number of paternal mitochondria transmitted into the central cell is greater than that transmitted into the egg as the result of preferential fertilization with the mitochondrion-rich dimorphic sperm cell, although the ratio of paternal to maternal mitochondria is 11,000 in the egg and 1820 in the central cell. The similarity in these ratios suggests that there is a critical dosage of mitochondria that is permissible within the zygotic and endospermatic lineages. This may represent either: (1) a maximum permissible value to prevent expression of paternal mitochondrial genome, (2) a minimum ratio required in order to permit recombination of maternal and paternal mitochondrial genomes, or (3) a cytoplasmic genome balance number.Abbreviations mtDNA mitochondrial DNA - Sua sperm cell unassociated with the vegetative nucleus - Svn sperm cell physically associated with the vegetative nucleus  相似文献   

13.
Summary One hundred and twenty-two varieties, lines and wild accessions of Lycopersicon were screened under three different regimes during the autumn/winter season of 1982–83 and 1983–84 for resistance to tomato leaf curl virus (TLCV). L. hirsutum f. glabratum (B6013) and L. hirsutum f. typicum (A1904) proved to be highly resistant to TLCV in all three environments. Various accessions of L. peruvianum were also highly resistant. L. pimpinellifolium (A1921) exhibited no TLCV symptoms within 90 days. Of the cultivated varieties, Acc 99 exhibited the minimim score for susceptibility; AC 142, Collection No. 2, Kalyanpur Angurlata and HS 101 had a low rating for virus incidence. The inheritance of resistance was studied in the interspecific crosses between a TLCV resistant line of L. pimpinellifolium (A1921) and five (HS 101, HS 102, HS 110, Pusa Ruby and Punjab Chhuhara) susceptible cultivars of L. esculentum. Parents, F1, F2 and backcross progenies were artificially inoculated with local strains of TLCV using vector the viruliferious whitefly, Bemisia tabaci (Genn.). Data indicated that the resistance of L. pimpinellifolium (A 1921) is monogenic and incompletely dominant over susceptibility.  相似文献   

14.
A detailed investigation of hydrodynamic and conformational behavior has been made of the HM-crystallin and -crystallins of bovine lens. Results from this study indicated that HM (high-molecular-weight -crystallin) and (low-molecular-weight -crystallin) possess considerable size and charge heterogeneities in their native structures and subunit polypeptides, respectively. Sedimentation velocity showed a heterogeneous polydisperse system of HM with an average sedimentation coefficient of about 50 S and a more homogeneous system of -crystallin of 20 S. Viscosity and circular dichroism studies pointed to a compact and globular shape of dominant -sheet conformation for -crystallin, yet a highly asymmetrical and aggregated form for HM. The conformational stability of -crystallin was investigated in the presence of various denaturants. The evidence presented shows that hydrogen bonding is the main force in maintaining the quaternary structure of compact native -crystallin. Conformational flexibility of -crystallin demonstrated in the equilibrium unfolding study indicated a multistep transition that made the extraction of thermodynamic data from the heat denaturation study difficult. Temperature perturbation on -crystallin suggested the possible involvement of hydrophobic interaction in the aggregation process, leading to the formation of HM from -crystallin. The comparison of conformational properties between HM and -crystallin strongly indicated that HM is a denatured form of -crystallin.  相似文献   

15.
sThe hydrolysis of several esters catalyzed by lipase of Candida rugosa was used to analyse the interaction between the ester substrate and the active site and the geometry and steric restrictions of alk, ar and h subsites. Using 4-R-C H -CH(R)-COOEt and ethyl trans-cinnamate, the presence of a low electronic density zone in the ar pocket is described, the dimensions of the pocket produced by Phe-296 and Leu-297 in the alk subsite and the size of the h subsite are described.  相似文献   

16.
Delicious apple (Malus domestica Borkh.) and several of its strains, which have been difficult to root in vitro, were successfully propagated with rooting percentages up to 100%. The combination of treatments used to achieve this result included placing the shoots on rooting medium in the dark at 30°C for the first week of the rooting stage, then moving them to a regime of 16 hr light-8 hr dark at 25°C. The rooting medium contained half strength Murashige and Skoog salts plus 1.2 M thiamine HCl, 0.56 mM myo-inositol, 1 mM phloroglucinol (PG), 1.4 M indolebutyric acid (IBA), 1.3 M gibberellic acid (GA3), 87.6 mM sucrose, and 7 g l–1 Difco Bacto agar. Dark treatment applied during the proliferation stage (etiolation) was less effective than one applied at the beginning of the rooting stage. The optimum length of dark treatment during rooting was 4 to 7 days. Increasing the temperature from 25°C to 30°C improved rooting of Delicious, Royal Red Delicious, and Vermont Spur Delicious in the absence of PG but generally had less effect in the presence of PG. Further increase in temperature to 35°C stimulated rooting of Royal Red Delicious but reduced rooting of Vermont Spur Delicious. Transfer of the cuttings to auxin-free medium after 1 week had no effect on percentage rooting and increased the number of roots per cutting for only 1 of 4 cultivars tested and then only in the presence of PG. In general PG stimulated rooting of Delicious and its strains, but had no effect on Golden Delicious.  相似文献   

17.
Summary The fertilizing ability of spermatozoa from epididymal tubules maintained in organ cultures from 1 to 7 days was assessed after artificial insemination into receptive does. It was found that spermatozoa from the distal corpus which were already capable of fertilizing eggs prior to the cultures retain this ability for 1 day without addition of hormone and for 3–4 days when testosterone (0.5 g/ml) or 5-dihydrotestosterone (0.5 g/ml) is added to the culture medium. Spermatozoa from the proximal corpus which were not capable of fertilizing eggs prior to the cultures remain so after 1 day in cultures without addition of hormone. Testosterone, 5-dihydrotestosterone, 3-androstanediol, or 3-androstanediol was added to cultures of proximal corpus at a concentration of 0.5 g/ml. Only with 5-DHT is the mean percentage of fertilization significantly higher than the percentage obtained without addition of hormone. Insulin does not potentiate the effect of 5-DHT on sperm fertilizing ability. Epithelial growth factor is ineffective. Spermatozoa from the caput epididymidis kept in cultures for 1 to 4 days remain infertile. The results are discussed in light of the morphological findings presented in the preceding communication and in relation to the physiological requirement for sperm maturation in the epididymis.  相似文献   

18.
Three Drosophila embryonic deoxyribonucleases, designated den1, den2 and den3, are identified in nuclear extracts separated by glycerol density gradient centrifugation. Den1, removes short products from the 5-ends of single-stranded DNA or double-stranded DNA with either blunt or 5-recessed termini. Den2 is inactive with single-stranded DNA and acts as 3-exonuclease with double-stranded DNA possessing either blunt or 3-recessed termini. Den3 preferentially uses partial duplex DNA containing single-stranded gap and it catalyzes hydrolysis, in 3-5 direction, of one of the shorter strands that flank the gap. Nucleolytic activities of den1, den2 and den3 are inhibited with ATP.  相似文献   

19.
The taxonomic significance of the trunk limbs of the chydoridae (Cladocera)   总被引:1,自引:1,他引:0  
N. N. Smirnov 《Hydrobiologia》1966,27(3-4):337-343
Summary The differences in the structure of the trunk limbs allow to outline three sections of Chydoridae (see table I and fig. 1), coinciding with the sections distinguished according to the structure of the head pores.
Chydoridae (Cladocera)
Chydoridae (. ), , .
  相似文献   

20.
Calf lens A-crystallin isolated by reversed-phase HPLC demonstrates a slightly more hydrophobic profile than B-crystallin. Fluorescent probes in addition to bis-ANS, like cis-parinaric acid (PA) and pyrene, show higher quantum yields or Ham ratios when bound to A-crystallin than to B-crystallin at room temperature. Bis-ANS binding to both A- and B-crystallin decreases with increase in temperature. At room temperature, the chaperone-like activity of A-crystallin is lower than that of B-crystallin whereas at higher temperatures, A-crystallin shows significantly higher protection against aggregation of substrate proteins compared to B-crystallin. Therefore, calf lens A-crystallin is more hydrophobic than B-crystallin and chaperone-like activity of -crystallin subunits is not quantitatively related to their hydrophobicity.  相似文献   

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