Are chemical barriers necessary for evolution of butterfly-plant associations?

Summary The association between heliconiine butterflies and Passion flower vines is composed of three or more subassociations, in which each Heliconius species group feeds on a different Passiflora subgenus. The relationships are consistent with the adaptive zone hypothesis of Ehrlich and Raven, which would suggest that (1) species of the subgenus Plectostemma proliferated as a result of chemical barriers to herbivory, which created a herbivore-free adaptive zone in which speciation and diversification took place, and (2) species of the H. erato-charitonia group overcame these barriers and entered a competitor-free adaptive zone, in which they proliferated and speciated with those plants as hosts. The hypothesis that plant secondary chemicals were responsible for creating such barriers to herbivory was tested using heliconiine species as bioassays, in which reduced growth rates indicated presence of chemical barriers to feeding. Contrary to expectation, plants of the subgenus Plectostemma showed little or no chemical defense against any species of heliconiine caterpillar. In contrast many plants of the primitive subgenus Granadilla possessed significant chemical barriers against herbivory by heliconiine larvae, excepting those species in the H. numata-melpomene species group. I concluded that chemical barriers to feeding were not responsible for proliferation and diversification in the subgenus Plectostemma, nor did chemicals create a competitor-free adaptive zone in which the H. erato-charitonia species-group could proliferate and speciate. Chemical barriers may have been important in the evolution of the subgenus Granadilla-heliconiine association. I suggest that plant allelochemics are only one of many possible barriers to herbivory which can help create adaptive zones for plants and their herbivores, and that the patterns of butterfly foodplant specialization discussed by Ehrlich and Raven (1964) are not necessarily the result of biochemical adaptation and counteradaptation.     

Is photobleaching necessary for Raman imaging of bone tissue using a green laser?

Raman microspectroscopy is widely used for musculoskeletal tissues studies. But the fluorescence background obscures prominent Raman bands of mineral and matrix components of bone tissue. A 532-nm laser irradiation has been used efficiently to remove the fluorescence background from Raman spectra of cortical bone. Photochemical bleaching reduces over 80% of the fluorescence background after 2 h and is found to be nondestructive within 40 min. The use of electron multiplying couple charge detector (EMCCD) enables to acquire Raman spectra of bone tissues within 1-5 s range and to obtain Raman images less than in 10 min.     

Is photobleaching necessary for Raman imaging of bone tissue using a green laser?

Raman microspectroscopy is widely used for musculoskeletal tissues studies. But the fluorescence background obscures prominent Raman bands of mineral and matrix components of bone tissue. A 532-nm laser irradiation has been used efficiently to remove the fluorescence background from Raman spectra of cortical bone. Photochemical bleaching reduces over 80% of the fluorescence background after 2 h and is found to be nondestructive within 40 min. The use of electron multiplying couple charge detector (EMCCD) enables to acquire Raman spectra of bone tissues within 1-5 s range and to obtain Raman images less than in 10 min.     

Is a decrease in cyclic AMP a necessary and sufficient signal for maturation of amphibian oocytes?

Acetylcholine rapidly lowered the intracellular levels of cyclic AMP in stage 5 and 6 Xenopus laevis oocytes. Acetylcholine alone did not induce oocyte maturation, though it did accelerate maturation induced by progesterone. The effect of acetylcholine on oocyte maturation was independent of extracellular calcium concentration. Adenosine increased cyclic AMP and abolished the progesterone-induced decrease in cyclic AMP levels in follicles and in denuded oocytes. This effect of adenosine was blocked by the Ra purinergic receptor antagonist, theophylline. Despite those effects, adenosine alone induced maturation in stage 6 oocytes and accelerated progesterone-induced maturation in both stage 5 and 6 cells. Adenosine also induced a significant increase in the rate of 45Ca efflux from oocytes in the presence and the absence of external calcium. We suggest that the activation of cell surface receptors involved in the release of calcium from cellular stores may induce or accelerate oocyte maturation independently of small changes in intracellular cyclic AMP concentration.     

Is Fisher's model necessary for the theory of population improvement?

Summary It is shown here that genetic advance in one cycle of recurrent selection can be formulated directly in terms of covariances between relatives by application of the general statistical principle of linear prediction. For practical use of such formulae it is necessary to estimate the corresponding covariance between relatives from the mating design used. With General Combining Ability selection such estimation is direct. For other types of selection, it is necessary to derive associated covariances from other types of covariances but it is not necessary to use classical results of covariances between relatives in terms of genetic effects. Indeed, covariances can be derived without factorial decomposition of the genetic effects at one locus, i.e., without the concept of additivity and dominance. This approach allows a simple derivation of the genetic advance after n cycles of selection, followed by m generations of intercrossing, with a minimum of assumptions.     

Is it necessary for screening irregular antibodies of blood donors?

To explore the necessity of electronic crossmatching applied to irregular antibodies from blood donors, to ensure blood transfusion safety. Irregular antibody screening was performed on blood samples collected in the Dongguan Blood Center from Apr 17, 2014 to Dec 31, 2017. Primary screening was performed on the Sanquin automatic blood group analyzer by the microcolumn gel method (Sanquin). The positive samples were analyzed again using the salt medium method, polybrene method and micro-column gel method (Diana) for the second screening. If the second screening was positive, it was used to determine irregular antibody specificity (using panel cells) and any irregular antibody titer was detected. A total of 208,004 samples were detected, of which 316 were positive (316/208,004; 0.152%). Among them, 120 alloantibodies (120/135,139; 0.088%) were detected in male donors, which was much lower than in female donors (173/72,865; 0.237%) (P<0.01). A total of 16 kinds of known irregular antibodies and 40 cases of unknown antibody specificity were detected, with 119 cases of IgG type and 197 cases of IgM type, at the ratio of 1.65:1. In female donors, the frequencies of anti-D, anti-E, anti-M and anti-Le^a were significantly higher than in male donors (P<0.01). In married couples, the frequencies of anti-D and anti-E were significantly higher than those unmarried (P<0.05). In minority nationalities, the frequency of anti-M was significantly higher than in the Han nationality (P<0.05). In non-Guangdong donors, the frequencies of anti-D and anti-Le^a were significantly higher than in Guangdong donors. 87.02% of irregular antibody positive donors’ antibody titers were lower than “++”, which was deemed as no serious hazard for clinical transfusion. The study suggests that it is unnecessary to screen for irregular antibodies in blood donors. Male donors from Guangdong may not be required to undergo screening for irregular antibodies, and anti-D and anti-E only identification is also not required to be detected in female donors.     

Is the nexus necessary for cell-to-cell coupling of smooth muscle?

Summary Electronmicroscopic study of electrically coupled smooth muscles was undertaken to determine the distribution of nexuses in various types of smooth muscle. The study revealed that while nexal structures were commonplace in some types of smooth muscle, they were very rare or absent in others, even though in some cases these cells were only a few nanometers distant from one another. The persistence in thin section of these structures in the main circular muscle of dog intestine after poor fixation, fixation under strain, cell shrinkage, and metabolic damage of various sorts seems to rule out the thesis that they are labile. The absence of nexuses in longitudinal muscle of dog intestine examined both by thin section and by freeze fracture suggests that in this tissue they are absent or very rarein vivo and cannot account for electrical coupling.Nexuses were discernible in thin sections of main circular muscle after a variety of experimental conditions of fixation. Metabolic inhibition orin vitro permanganate fixation partially destroyed nexal contacts. These procedures induced tissue, membrane apposition and an accompanying increase in the number of structures which resemble nexuses at low magnification (nexus-like structures). Nexus-like structures occurred in all smooth muscle fixed byin vitro permanganate associated with apposition of membranes and poor preservation of basement membrane. A technique ofin vitro permanganate fixation was developed which prevented tissue swelling; consequently nexus-like structures were absent in tissues so treated. The suggestion is made that some structures described in the literature as nexuses, following permanganate fixation, may represent nexus-like structures.The balance of evidence suggests that nexuses need not be present for electrical coupling of some smooth muscle cells, in which other types of cell-to-cell contacts must be invoked.     

Is it necessary for screening irregular antibodies of blood donors?

To explore the necessity of electronic crossmatching applied to irregular antibodies from blood donors, to ensure blood transfusion safety. Irregular antibody screening was performed on blood samples collected in the Dongguan Blood Center from Apr 17, 2014 to Dec 31, 2017. Primary screening was performed on the Sanquin automatic blood group analyzer by the microcolumn gel method (Sanquin). The positive samples were analyzed again using the salt medium method, polybrene method and micro-column gel method (Diana) for the second screening. If the second screening was positive, it was used to determine irregular antibody specificity (using panel cells) and any irregular antibody titer was detected. A total of 208,004 samples were detected, of which 316 were positive (316/208,004; 0.152%). Among them, 120 alloantibodies (120/135,139; 0.088%) were detected in male donors, which was much lower than in female donors (173/72,865; 0.237%) (P<0.01). A total of 16 kinds of known irregular antibodies and 40 cases of unknown antibody specificity were detected, with 119 cases of IgG type and 197 cases of IgM type, at the ratio of 1.65:1. In female donors, the frequencies of anti-D, anti-E, anti-M and anti-Le^a were significantly higher than in male donors (P<0.01). In married couples, the frequencies of anti-D and anti-E were significantly higher than those unmarried (P<0.05). In minority nationalities, the frequency of anti-M was significantly higher than in the Han nationality (P<0.05). In non-Guangdong donors, the frequencies of anti-D and anti-Le^a were significantly higher than in Guangdong donors. 87.02% of irregular antibody positive donors’ antibody titers were lower than “++”, which was deemed as no serious hazard for clinical transfusion. The study suggests that it is unnecessary to screen for irregular antibodies in blood donors. Male donors from Guangdong may not be required to undergo screening for irregular antibodies, and anti-D and anti-E only identification is also not required to be detected in female donors.     

Is a decline in offspring quality a necessary consequence of maternal age?

Recent studies in two species of Drosophila have demonstrated a negative effect of parental age on offspring fitness, including a reduced hatch rate of eggs and larval-to-adult viability. This has led to a call to consider the decline of offspring quality as a function of parental age in theoretical considerations of the evolution of ageing. We have tested whether a decline in egg and larval quality of older mothers is a general feature of senescence by examining it in the cockroach Nauphoeta cinerea. We also tested whether maternal age affected the reproductive potential of daughters. Although maternal age at first reproduction profoundly affected maternal fitness, there was no difference in hatch rate or larval viability between the offspring of young and old mothers. Likewise, the reproductive potential of the daughters of young and old mothers was the same. Thus, while maternal age effects may be important aspects of ageing in some systems, the generality and overall importance for theories of ageing remain unclear.     

SAPHO syndrome: Is a range of pathogen-associated rheumatic diseases extended?

SAPHO syndrome, representing a constellation of synovitis, acne, palmo-plantar pustulosis, hyperostosis, and osteitis, is now recognized as a distinct medical entity: a reactive infectious osteitis. Genetic, immunological, and bacterial mechanisms are implicated in the development of the disease. Diagnostic problems may arise due to non-complete manifestations of SAPHO: either acne and arthritis or acne and anterior wall osteitis with an unclear pustulosis history. The interventional study of Assmann et al. is a significant addition to a long range of publications showing an association of SAPHO with Propionibacterium acnes. Randomized control studies are needed to confirm the effects of antibiotic therapy.     

Human grief: Is its intensity related to the reproductive value of the deceased?

Thurstone's method of comparative judgement was used to measured the intensity of grief that parents of high-, moderate-, and low-reproductive value were expected to experience at the death of male and female children of different ages. The results were correlated with reproductive values for male and female British Columbians and for !Kung Bushwomen. Grief ratings were more highly correlated with reproductive value than with age and more highly correlated with reproductive values of !King Bushwomen than with those of British Columbians. The correlations were higher for male- than for female-stimulus children. The correlations of female ratings with reproductive value were higher than male ratings with reproductive value, although not as high as expected. However, the correlation between grief ratings and reproductive value did not increase as the reproductive value of the raters declined.     

Is a rise in intracellular concentration of free calcium necessary or sufficient for stimulated cytoskeletal-associated actin?

The addition of the calcium ionophore A23187 to rabbit neutrophils increases the amount of actin associated with the cytoskeleton regardless of the presence or absence of calcium in the incubation medium. In the presence of extracellular calcium, the effect of A23187 is biphasic with respect to concentration. The action of the ionophore is rapid, transient, and is inhibited by pertussis toxin, hyperosmolarity, and quinacrine. On the other hand, the addition of pertussis toxin or hyperosmolarity has small if any, effect on the rise in intracellular calcium produced by A23187. While quinacrine does not affect the fMet-Leu-Phe-induced increase in cytoskeletal actin and the polyphosphoinositide turnover, its addition inhibits completely the stimulated increase in Ca-influx produced by the same stimulus. The results presented here suggest that a rise in the intracellular concentration of free calcium is neither necessary nor sufficient for the stimulated increase in cytoskeletal-associated actin. A possible relationship between the lipid remodeling stimulated by chemoattractants and the increased cytoskeletal actin is discussed.     

Parasites lost? An overlooked hypothesis for the evolution of alternative reproductive strategies in amphibians

Amphibians exhibit the greatest diversity of reproductive strategies of all tetrapod vertebrates. While authors have traditionally attributed the evolution of these strategies to factors such as complex topography, unpredictable larval environments, and predation on larvae and eggs, support for any of these hypotheses has been limited. Importantly, most authors have ignored parasites, including unicellular pathogens and multicellular parasites, as selective agents capable of influencing amphibian evolution. Insights in disease transmission, amphibian immunity, and their interaction with various life histories require that we consider parasites to be selective pressures in our exploration of the evolution of amphibian reproductive strategies. I review recent findings and describe how these principles converge to form a novel conceptual hypothesis for the evolution of alternative reproductive strategies in amphibians. I offer some specific predictions and recommend that parasites be considered with other selective pressures when constructing formal, falsifiable hypotheses during evaluative studies of amphibian reproductive behavior.     

Cognitive effects of variations in pubertal timing: Is puberty a period of brain organization for human sex-typed cognition?

There is considerable interest in the organizational effects of pubertal sex hormones on human sex-related characteristics. Recent evidence from rodents suggests that there is a decreasing window of sensitivity to sex hormones throughout adolescence. If adolescence also represents a period of brain organization in human beings, then the timing of exposure to sex-typical hormones at puberty should have long-term effects on sex-typed characteristics: individuals with early timing should be more sex-typed than individuals with late timing. We tested this hypothesis in 320 young adults by relating their pubertal timing (retrospective comparison to peers) to cognitive abilities that show sex differences. Results provide partial support for the hypothesis. For men, pubertal timing was inversely related to scores on a test of three-dimensional mental rotations. Effects do not appear to be due to duration of hormone exposure (time since puberty), but other potential influences need further study.