A study of inheritance of white spots on the shell of <Emphasis Type="Italic">Littorina obtusata</Emphasis> (Gastropoda,Prosobranchia)

The hypothesis on monogenic inheritance of white spot pattern on the shell of the gastropod snail Littorina obtusata was tested. Although in most cases our results did not contradict this assumption, the hypothesis cannot explain the observed segregation in general. An alternative hypothesis was suggested, according to which the presence of spot pattern is controlled by two complementary biallelic genes.     

Parameters of brown-headed cowbird Molothrus ater egg discrimination in warbling vireos Vireo gilvus

We examined which egg parameters warbling vireos Vireo gilvus use to discriminate brown-headed cowbird Molothrus ater eggs and, by comparing our results to other studies, tested the prediction that ejecter species with eggs more similar in appearance to cowbird eggs will be less tolerant of foreign eggs. In addition, we tested the hypothesis that egg characteristics influence the cost of ejection and probability of committing ejection errors. Warbling vireos ejected 100% of eggs with a cowbird spot pattern and only spot pattern significantly influenced the probability of ejecting a foreign egg, whereas size and nest stage did not. Foreign eggs that differed in two parameters were not ejected significantly more than those that differed in one parameter. Thus, warbling vireos appear to be less tolerant of foreign eggs than species with eggs more divergent from cowbird eggs. There was no significant difference in the number of vireo eggs that were damaged when foreign eggs of different sizes and spot patterns were ejected, which is counter to the assumptions of the evolutionary equilibrium hypothesis. Similarly, foreign egg characteristics did not significantly influence the probability of ejection errors. Finally, egg discrimination in warbling vireos appears to have evolved directly to counter cowbird parasitism because all conspecific eggs switched into their nests were accepted.     

Female mate preference explains countergradient variation in the sexual coloration of guppies (Poecilia reticulata)

We tested the hypothesis that mate choice is responsible for countergradient variation in the sexual coloration of Trinidadian guppies (Poecilia reticulata). The nature of the countergradient pattern is that geographical variation in the carotenoid content of the orange spots of males is counterbalanced by genetic variation in drosopterin production, resulting in a relatively uniform pigment ratio. A female hue preference could produce this pattern, because hue is the axis of colour variation most directly affected by the pigment ratio. To test this hypothesis, we crossed two populations differing in drosopterin production and produced an F(2) generation with variable drosopterin levels. When the carotenoid content of the orange spots was held constant, female guppies preferred males with intermediate drosopterin levels. This shows that females do not simply prefer males with greater orange spot pigment content; instead, the ratio of the pigments also affects male attractiveness. To our knowledge, this is the first direct evidence for a hypothesized agent of countergradient sexual selection.     

Can whisker spot patterns be used to identify individual polar bears?

Studies of population dynamics, movement patterns and animal behavior usually require identification of individuals. We evaluated the reliability of using whisker spot patterns to noninvasively identify individual polar bears Ursus maritimus . We obtained the locations of polar bear whisker spots from photographs taken in western Hudson Bay, tested the independence of spot locations, estimated the complexity of each spot pattern in terms of information and determined whether each whisker spot pattern was reliable from its information content. Of the 50 whisker spot patterns analyzed, 98% contained enough information to be reliable, and this result varied little among observers. Photographs taken <50 m from polar bears were most useful. Our results suggest that individual identification of polar bears in the field based on whisker spot pattern variations is reliable. Researchers studying polar bear behavior or estimating population parameters can benefit from this method if proximity to the bears is feasible.     

Drosophila suzukii wing spot size is robust to developmental temperature

Phenotypic plasticity is an important mechanism allowing adaptation to new environments and as such it has been suggested to facilitate biological invasions. Under this assumption, invasive populations are predicted to exhibit stronger plastic responses than native populations. Drosophila suzukii is an invasive species whose males harbor a spot on the wing tip. In this study, by manipulating developmental temperature, we compare the phenotypic plasticity of wing spot size of two invasive populations with that of a native population. We then compare the results with data obtained from wild‐caught flies from different natural populations. While both wing size and spot size are plastic to temperature, no difference in plasticity was detected between native and invasive populations, rejecting the hypothesis of a role of the wing‐spot plasticity in the invasion success. In contrast, we observed a remarkable stability in the spot‐to‐wing ratio across temperatures, as well as among geographic populations. This stability suggests either that the spot relative size is under stabilizing selection, or that its variation might be constrained by a tight developmental correlation between spot size and wing size. Our data show that this correlation was lost at high temperature, leading to an increased variation in the relative spot size, particularly marked in the two invasive populations. This suggests: (a) that D. suzukii's development is impaired by hot temperatures, in agreement with the cold‐adapted status of this species; (b) that the spot size can be decoupled from wing size, rejecting the hypothesis of an absolute constraint and suggesting that the wing color pattern might be under stabilizing (sexual) selection; and (c) that such sexual selection might be relaxed in the invasive populations. Finally, a subtle but consistent directional asymmetry in spot size was detected in favor of the right side in all populations and temperatures, possibly indicative of a lateralized sexual behavior.     

An Opposite Pattern to the Conventional Thermal Hypothesis: Temperature-Dependent Variation in Coloration of Adults of Saccharosydne procerus (Homoptera: Delphacidae)

Melanism is a common polymorphism in many insect species that also influences immune function. According to the thermal melanin hypothesis, ectothermic individuals from cooler environments have darker cuticles and higher polyphenol oxidase (PO) levels, which represent a better immunocompetence. In this study, the links among environmental temperature, melanism, and PO activity of Saccharosydne procerus (Matsumura) were examined. Most S. procerus have a black spot on their forewings at high temperatures in the field and in the laboratory. In PO activity assay, a positive association between PO level and temperature was found. Our results showed that a diversification of melanism occurred under different temperatures and that melanism in S. procerus presented an opposite pattern to the one proposed by the thermal hypothesis.     

株行距配置对高产夏玉米冠层结构及籽粒灌浆特性的影响

在75000株·hm^-2种植密度下,选用郑单958和先玉335为试验材料,设置2种行距配置(等行距、宽窄行)和3种留苗方式(每穴1株、每穴2株、每穴3株),研究了6种种植方式对黄淮海地区高产夏玉米产量构成、吐丝后冠层结构及光合性能的调控作用,并以Richards模型拟合籽粒灌浆过程.结果表明： 产量、干物质积累量、作物生长率、灌浆速率、冠层光合能力等均表现为宽窄行处理高于等行距处理,留苗方式以每穴2株最高.各种植方式中以宽窄行每穴2株种植产量最高,达13.12（郑单958）和13.72（先玉335） t·hm^-2.宽窄行每穴2株种植改善了冠层内部光照状况,净光合速率和叶面积指数均有所提高,同时缓解了植株个体与群体间的矛盾,籽粒灌浆能力增强,干物质积累量提高.因此,宽窄行每穴2株种植是黄淮海夏玉米高产条件下产量提高的有效栽培方式.     

Separation of bovine spermatozoa proteins using 2D-PAGE revealed the relationship between tektin-4 expression patterns and spermatozoa motility

Poor semen quality has long been associated with bull infertility. However, the molecular basis in spermatozoa cells underlying the mechanisms of bull infertility remain unknown. The purpose of this study was to determine whether there is any protein in bovine spermatozoa related to semen quality. Semen samples from 18 Brahman bulls, 3 to 10 yrs of age, were assessed for semen quality in terms of spermatozoa motility and spermatozoa morphology. Spermatozoa extracts were separated using 2D-PAGE followed by staining with Coomassie blue. At least one duplicate gel was performed for each sample. Each gel was scanned with an ImageScanner System and analyzed for spots by ImageMaster 2D platinum software. The related protein spot(s) with semen quality was cut from the gel and identified by LC MS/MS. The results showed that at least 600 protein spots were detected in the spermatozoa extracts of the Brahman bulls. Of all these spots, there were 3 of 56 kDa at pI 6.4, 6.6 and 6.8 (Z₁, Z₂ and Z₃, respectively) that clearly showed different expression pattern among 18 Brahman bulls. Of 18 bulls (a) five showed the presence of spot Z₁ and Z₂ (pattern A) (b) one of spot Z₃ (pattern B) (c) five of spot Z₂ and Z₃ (pattern C) (d) one of spot Z₁ (pattern D) and (e) six of spot Z₂ (pattern E). Identification of spot Z₁, Z₂ and Z₃ by LC MS/MS had a similar result as matched to the tektin-4 protein of Bos taurus with a respective score of 171, 557 and 591. The statistical analysis of the 56 kDa protein patterns, tektin-4, indicated a significant effect on spermatozoa motility (P < 0.05) albeit non-significant on spermatozoa morphology. The bulls which showed pattern A had a higher percentage of spermatozoa motility than pattern E (P < 0.05) and not different from pattern C (P > 0.05). The statistical analysis also revealed that the presence of spot Z₁ had an effect on the percentage of spermatozoa motility (P < 0.01), whereas the presence of spot Z₂ and Z₃ had no effect (P > 0.05). The correlation coefficient between the relative protein content of spot Z₁ and the percentage of spermatozoa motility was 0.49. Our study demonstrates that the expression patterns of tektin-4 were a proxy for an effect on spermatozoa motility and consequently bull infertility. It may be that these protein patterns can be used as markers for improving bovine reproduction.     

Effects of experimental calcium availability,egg parameters and laying order on Great Tit Parus major eggshell pigmentation patterns

Many bird species lay eggs speckled with protoporphyrin‐based spots, however, for most of them the function of eggshell spotting is unknown. A plausible hypothesis is that protoporphyrin might have a structural function in strengthening the eggshell and is therefore deposited when calcium is scarce. In this study, we experimentally provided Great Tit Parus major females with supplemental calcium to examine its effect on the protoporphyrin‐based maculation of their eggs. In addition, we studied variation in eggshell pigmentation patterns in relation to other egg parameters and laying order. Calcium‐supplemented females laid larger eggs but shell thickness was not significantly affected by the treatment. Calcium supplementation may reduce the time and energy females devote to searching for calcium‐rich material, so that they can collect more nutrients and so lay larger eggs. Furthermore, pigment darkness was associated with egg volume and shape, which suggests that female quality and environmental food availability may also influence the shell pigmentation pattern. Within clutches, later‐laid eggs had larger and darker spots that were distributed more unevenly on the shell surface. This within‐clutch pattern could be explained by the increase in egg volume and egg shape and a decline in shell thickness with egg‐laying order, which characteristics were all related to shell‐spotting pattern. Eggs with a coronal ring had thinner shells, but pigment intensity and spot size were not related to shell thickness. Thus, our results suggest that concentrated spotting distribution may have a mechanical function, supporting the structural‐function hypothesis.     

Two-dimensional cryostat section electrophoresis: a novel method and its application to the diseased synovial membrane

Summary A two-dimensional electrophoresis technique for analysing sections of human tissue is described. Cryostat sections, 10 μm thick, are placed on an isoelectric focusing gel and then transfered to an SDS gel in the second dimension. The protein pattern is visualized by silver staining and is thought to represent soluble proteins. The silver-stained proteins were found to be both reproducible and, to the extent tested, organ-specific. This method was used to analyse 43 synovial membranes from patients suffering from rheumatoid arthritis or degenerative joint diseases. The analysis did not reveal any specific protein pattern for rheumatoid arthritis. The protein spot number was not related to the cause of arthritis. However, the total protein spot number was related to the histomorphological synovitis type, with those exhibiting either an exudative or proliferative synovitis pattern possessing significantly higher protein spot numbers than those specimens exhibiting a sero-fibrous or lympho-plasmacytic pattern of synovitis.     

Geographical variation of elytral spot patterns in the phytophagous ladybird,Epilachna vigintioctopunctata (Coleoptera: Coccinellidae) in the Province of Sumatera Barat,Indonesia

Geographical variation in the elytral spot patterns of a phytophagous ladybird, Epilachna vigintioctopunctata, was studied in the Province of Sumatera Barat, Indonesia. Populations of E. vigintioctopunctata were divided into four major groups (I–IV) by the incidence of spot pattern variations. Group I, occurring in the coastal plains and inland lowlands, and Group IV, confined to the highlands, were the extremes of the spot pattern variations, the latter had many more non-persistent spots and confluences with larger body size and advanced melanism than the former. These two groups were connected with each other via the intermediate groups. A positive relationship was detected between the elevations of sample sites and the average number of non-persistent spots per elytron. Consequently, present results favor the view that the two previously recognized forms of E. vigintioctopunctata (formae A and B inKatakura et al., 1988) represent a complicated intraspecific variation rather than two distinct sibling species. Elytral spot pattern variations were not different between the sexes or between the beetles collected from different kinds of host plants.     

Pattern formation of the 'Tilapia mark' in the tilapia fish, Oreochromis mossambicus

The dorsal fin of the larval and juvenile Oreochromis mossambicus exhibits a unique black spot known as the ' Tilapia mark'. We traced its development and found that it occupied a specific position in the dorsal fin bounded by rays 15 and 20. Ablation experiments carried out on the larval dorsal fin showed that this spot region constituted a developmental positional field. This positional field in the fin could regenerate and re-establish the spot pattern despite repeated perturbation. The re-establishment of spot was not simply due to fin injury since ablation of the non-spotted region of the dorsal and the tail fin did not result in aggregation of melanophores. We propose that that' Tilapia mark' is a result of positional information in operation.     

Granulometric analysis of spots in DNA microarray images

As the topological properties of each spot in DNA microarray images may vary from one another, we employed granulometries to understand the shape-size content contributed due to a significant intensity value within a spot. Analysis was performed on the microarray image that consisted of 240 spots by using concepts from mathematical morphology. In order to find out indices for each spot and to further classify them, we adopted morphological multiscale openings, which provided microarrays at multiple scales. Successive opened microarrays were subtracted to identify the protrusions that were smaller than the size of structuring element. Spot-wise details, in terms of probability of these observed protrusions,were computed by placing a regularly spaced grid on microarray such that each spot was centered in each grid. Based on the probability of size distribution functions of these protrusions isolated at each level, we estimated the mean size and texture index for each spot. With these characteristics, we classified the spots in a microarray image into bright and dull categories through pattern spectrum and shape-size complexity measures. These segregated spots can be compared with those of hybridization levels.     

Glial Fibrillary Acidic Protein: Norepinephrine Stimulated Phosphorylation in Intact C-6 Glioma Cells

Abstract: Coelectrophoresis in two-dimensional gels of rat glial fibrillary acidic protein (GFA) and ³²P-labeled whole cell extracts of rat C-6 glioma cells showed that the GFA migrated in close proximity to a previously noted phosphoprotein, 50K-6.1, of these cells. GFA electrophoresed as a 50K polypeptide with at least four charge variants, the most acidic of which coelectrophoresed with 50K-6.1. Exposure of the C-6 cultures to dibutyryl cyclic AMP (dbcAMP) for 48 h increased the relative abundance of the endogenous polypeptide associated with 50K-6.1 by threefold, consistent with the hypothesis that 50K-6.1 was GFA. Norepinephrine stimulated 50K-6.1 phosphorylation 3.2-fold in dbcAMP-induced cultures. Peptide mapping with V8 protease and subtilisin was used to test the hypothesis that GFA and 50K-6.1 were identical polypeptides. With V8 protease, the peptides generated from the [³⁵S]methionine labeled putative GFA spot of the C-6 cells were indistinguishable from the stained bands derived from authentic GFA in mixed samples of the two proteins. Likewise, the ³⁵S-labeled acidic satellite to the putative GFA spot also yielded a peptide map that matched that of the authentic GFA. ³²P-labeled peptides derived from the 50K-6.1 protein were a subset of those from authentic GFA. With three subtilisin concentrations, ³²P-labeled 50K-6.1 was degraded to peptides which were again a subset of the stained GFA peptides. A cytoskeletal fraction from ³²P-labeled C-6 cells contained a 50K phosphoprotein. Pep-, tide mapping with V8 protease produced a ³²P-peptide pattern which was a subset of that from authentic GFA. The pattern closely resembled the ³²P-peptide pattern for the 50K-6.1 protein from 2-dimensional gels of whole cell extract. It was concluded that the protein 50K-6.1 is a phosphorylated form of GFA and that GFA is a phosphoprotein whose phosphòrylation is stimulated by norepinephrine in C-6 glioma cells.     

Differential cell analysis of cytocentrifuged bronchoalveolar fluid samples affected by the area counted

OBJECTIVE: To investigate variations in the differential cell counts between the quadrants of cytocentrifuged bronchoalveolar lavage (BAL) fluid preparations and to evaluate the diagnostic impact of these differences in interstitial lung diseases (ILD). STUDY DESIGN: BAL fluid samples obtained from 30 patients suspected of having ILD or pneumonia were cytocentrifuged and additionally stained with May-Grünwald-Giemsa stain. Two observers differentiated 200 cells in each quadrant as well as in a circular pattern around the center of the cytocentrifuge spot. RESULTS: Lymphocytes and alveolar macrophages were not randomly distributed on the cytocentrifuge spot. Ten samples of patients with histologically confirmed ILD were selected to test the diagnostic impact using a validated computer program. The predicted diagnosis did not correspond to the histologic diagnosis for one quadrant from 1 of these 10 samples (sarcoidosis instead of idiopathic pulmonary fibrosis), whereas the differential cell counts performed around the center of the cytocentrifuge spot provided the correct diagnosis in all cases. CONCLUSION: BAL fluid differential cell counts varied between the quadrants of the cytocentrifuge spot. The center of the cytocentrifuge spot appeared to be the most reliable area. Therefore, cell counting is recommended in a circular pattern around the center of the cytocentrifuge spot.     

The Engrailed-expressing secondary head spots in the embryonic crayfish brain: examples for a group of homologous neurons in Crustacea and Hexapoda?

Hexapoda have been traditionally seen as the closest relatives of the Myriapoda (Tracheata hypothesis) but molecular studies have challenged this hypothesis and rather have suggested a close relationship of hexapods and crustaceans (Tetraconata hypothesis). In this new debate, data on the structure and development of the arthropod nervous system contribute important new data ("neurophylogeny"). Neurophylogenetic studies have already provided several examples for individually identifiably neurons in the ventral nerve cord that are homologous between insects and crustaceans. In the present report, we have analysed the emergence of Engrailed-expressing cells in the embryonic brain of a parthenogenetic crayfish, the marbled crayfish (Marmorkrebs), and have compared our findings to the pattern previously reported from insects. Our data suggest that a group of six Engrailed-expressing neurons in the optic anlagen, the so-called secondary head spot cells can be homologised between crayfish and the grasshopper. In the grasshopper, these cells are supposed to be involved in establishing the primary axon scaffold of the brain. Our data provide the first example for a cluster of brain neurons that can be homologised between insects and crustaceans and show that even at the level of certain cell groups, brain structures are evolutionary conserved in these two groups.     

An hypothesis concerning the role of the Golgi apparatus in the phenomenon of memory

The hypothesis considers the anatomy and physiology of the memory-storing neuron from the viewpoint that an eccentrically placed nucleus with a Golgi Apparatus situated between it and the proximate cell membrane could be the mechanism for the storage and retrieval of experience and thought processes. Metabolites which enter the Golgi Apparatus are filtered and refined before being discharged from the surface which faces the cell membrane. They travel by the shortest route to a special location on the nearest part of the cell membrane. At this "favoured spot" the action potential is reactivated before the metabolites reach other parts of the membrane. Afferent impulses arriving via the synapses at the "favoured spot" and its tributary dendrites have priority controls the specific polarity of the cell, enabling it to record, store and reproduce the memory of its initial stimulus. Reinforcing stimuli cause the eccentric nucleus and Golgi Apparatus to move nearer to the favoured spot. This mechanism could be the basis of memory. The hypothesis may be applied to other observed phenomenon of brain function and might be submitted to experiment confirmation.     

Relationship of chin spot size to dominance in the black-chinned mouthbrooding cichlid fish (Sarotherodon melanotheron)

Aggressive interactions of male Sarotherodon melanotheron were studied to determine the communicative value of chin spot size in relation to dominance. In addition, the effects of residency and size on the aggressiveness of this fish were determined. Two-factor analysis of variance was used for frequencies of each modal action pattern for residency and size. Results show that residency played a major role in the outcome of an aggressive interaction, whereas size had little effect. Dominance of each experimental fish was calculated using Barlow & Ballin's (1976) dominance index. A chin spot ratio was obtained by dividing the chin spot area by the total surface area of the individual fish. Simple linear regression was conducted to determine if dominance and chin spot size were correlated and a positive linear relationship was found to exist between the two variables.