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1.
Sexually selected infanticide is an important source of infant mortality in many mammalian species. In species with long-term male-female associations, females may benefit from male protection against infanticidal outsiders. We tested whether mountain gorilla (Gorilla beringei beringei) mothers in single and multi-male groups monitored by the Dian Fossey Gorilla Fund’s Karisoke Research Center actively facilitated interactions between their infants and a potentially protective male. We also evaluated the criteria mothers in multi-male groups used to choose a preferred male social partner. In single male groups, where infanticide risk and paternity certainty are high, females with infants <1 year old spent more time near and affiliated more with males than females without young infants. In multi-male groups, where infanticide rates and paternity certainty are lower, mothers with new infants exhibited few behavioral changes toward males. The sole notable change was that females with young infants proportionally increased their time near males they previously spent little time near when compared to males they had previously preferred, perhaps to encourage paternity uncertainty and deter aggression. Rank was a much better predictor of females’ social partner choice than paternity. Older infants (2–3 years) in multi-male groups mirrored their mothers’ preferences for individual male social partners; 89% spent the most time in close proximity to the male their mother had spent the most time near when they were <1 year old. Observed discrepancies between female behavior in single and multi-male groups likely reflect different levels of postpartum intersexual conflict; in groups where paternity certainty and infanticide risk are both high, male-female interests align and females behave accordingly. This highlights the importance of considering individual and group-level variation when evaluating intersexual conflict across the reproductive cycle. 相似文献
2.
Frankia is the diverse bacterial genus that fixes nitrogen within root nodules of actinorhizal trees and shrubs. Systematic and ecological
studies of Frankia have been hindered by the lack of morphological, biochemical, or other markers to readily distinguish strains. Recently,
nucleotide sequence of 16 S RNA from the small ribosomal subunit has been used to classify and identify a variety of microorganisms.
We report nucleotide sequences from portions of the 16 S ribosomal RNA from Frankia strains AcnI1 isolated from Alnus viridis ssp. crispa (Ait.) Turrill and PtI1 isolated from Purshia tridentata (Pursh) DC. The number of nucleotide base substitutions and gaps we find more than doubles the previously reported sequence
diversity for the same variable regions within other strains of Frankia. 相似文献
3.
Ramesh Chand Manoj Kumar Chanda Kushwaha Kavita Shah Arun K. Joshi 《Current microbiology》2014,69(2):202-211
Eighteen barley isolates of Bipolaris sorokiniana belonging to wild and clonal type of black, mixed and white subpopulations were quantitatively assayed for their melanin content and aggressiveness with respect to production of some of the extracellular enzymes such as cellulase, pectinase, amylase and protease. Cellulase and pectinase constituted major portion of the enzymes recovered from the black, mixed and white isolates. Enzyme production and aggressiveness were relatively higher in melanin devoid or low melanin isolates. The melanin deficient isolates were also differentiated from black and mixed isolates on the basis of variation in internal transcribed spacer region of the ribosomal DNA. Higher enzyme productions positively correlated with area under disease progress curve (AUDPC) and lesion development. Melanin content was negatively correlated with extracellular enzymes and aggressiveness of the isolates. Based on melanin content, lesion size, AUDPC and extracellular enzymes, the isolates were grouped in two major clusters (I and II) with further division of cluster II into two sub-clusters (II-A and II-B). The results appears to indicate a possible role of melanin in release of extracellular enzymes and hence in evolution and selection of aggressive isolates of B. sorokiniana in barley. 相似文献
4.
S. P. Goyal P. K. Ghosh T. O. Sasidharan Phool Chand 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,158(1):127-134
Summary The relative body water conservation efficiency of two Indian desert gerbil species,Meriones hurrianae (diurnal/crepuscular) andTatera indica (nocturnal), has been examined under near-natural conditons in different seasons.A mean urine osmolarity of 3180 mosmol/l (maximum 4645 mosmol/l) inM. hurrianae and a mean value of 5128 mosmol/l (maximum 7547 mosmol/l) inT. indica have been recorded during summer.Urine osmolarity and urea levels indicated that whileM. hurrianae remain sufficiently hydrated mainly by virtue of their feeding habit,Tatera indica may depend on the relatively higher concentrating capacity of their kidneys. 相似文献
5.
Arvind Kumar Bhatt Tek Chand Bhalla Hari Om Agrawal N. Sharma 《Letters in applied microbiology》1992,15(1):1-4
An extracellular chitosanase produced by Rhodotorula gracilis CFR-1 that catalyses a limited degradation of chitosan with no detectable generation of glucosamine or reducing groups was identified. Ultracentrifugation, polyacrylamide gel electrophoresis and gel permeation studies suggest that chitosan of average molecular mass 36000 Da was reduced by the enzymic catalysis to nearly one-fourth this size without further hydrolysis of the products. The enzyme, produced constitutively by this yeast, was partially purified and some of its properties were studied. 相似文献
6.
Primary structure of -chain of pigeon is presented. It was determined by amino acid sequence analysis of intact -chain and its peptides obtained by the enzymatic and chemical cleavage. Comparison of amino acid sequence of the chain with other available data shows 14 Ile, 61 Lys, and 113 Ile as residues specific to pigeon. One important replacement at 11 contact is 55 MetSer. 相似文献
7.
T K Kobayashi T Yamaki E Yoshino S Terawaki K Tara K Nishida I Sawaragi 《Acta cytologica》1983,27(3):281-284
A case of meningitis due to Acinetobacter calcoaceticus occurred after neurosurgery. The cerebrospinal fluid cytology showed intracellular diplococci that strongly resembled Neisseria meningitidis. However, subsequent bacteriologic studies revealed a bacterium identical to A. calcoaceticus. It is of practical importance for cytology laboratories to recognize this diplococcal form of organism. 相似文献
8.
The karyotypes of Renanthera storiei and Trichoglottis fasciata and the meiotic behavior in their hybrid were investigated. Considerable differences in chromosome morphology were observed for the two species. The karyotype of R. storiei was more asymmetrical with a lower mean F percentage than that of T. fasciata. Also, variation in the largest pair of chromosomes as well as in the satellite chromosomes was apparent. Meiosis in the hybrid was highly irregular. Observations on karyotypes and meiotic behavior indicate a more distant relationship between Trichoglottis and Renanthera than among Renanthera, Arachnis, and Vandopsis. 相似文献
9.
Baljinder Singh Devinder Dhawan Bakhshi Chand Pralhad Chand Mangal 《Biological trace element research》1994,40(3):287-293
The impact of lead as an environmental pollutant on the I-131 uptake and retention in rat thyroid was assayed alone and in combination with lithium treatment. Lead treatment significantly stimulated the 2- and 24-h uptake of I-131 in the thyroid, and the 24-h uptake showed the maximum stimulation after 3 mo of lead treatment. On the contrary, lithium supplementation reduced the uptake significantly and the maximum decrease was noticed after 2 mo of lithium administration. Further, simultaneous lead and lithium treatment resulted in more pronounced increase in the uptake of I-131 by the thyroid, which was maximum after 3 mo of combined treatment. The thyroidal biological half-life of I-131 (T biol) was found to be increased significantly following lead and lithium treatments when given separately. Interestingly, combined lead and lithium treatment given up to 2 mo further prolonged theT biol of I-131, thus reflecting its increased retention. 相似文献
10.
To study the influence of soil moisture on phosphorus (P) depletion in the rhizosphere, maize (Zea mays cv. Trak) was pre-grown in vermiculite filled-PVC tubes for 9 days and then the plants with the tubes were transplanted into soil columns maintained at two soil moisture levels () of 0.14 and 0.20 cm3 cm–3 for 10 days. The soil columns were separated at 1 cm depth by a nylon screen of 53 m inner mesh size, into 1 cm soil layer above and 3 cm soil column below screen. A root mat developed over the screen, but root hairs only could penetrate it. Regardless of the soil moisture level in the columns, and adequate and equal water and nutrients supply was maintained via wicks from an external nutrient solution to the plant roots in vermiculite. After 10 days, the soil columns were separated from the root mats, quickly frozen in liquid nitrogen and sliced into thin layers (0.2mm) using a refrigerated microtome to give soil samples at defined distances from the root mats for analyses. Lower soil moisture (=0.14) resulted in narrower and steeper depletion profile of 0.5 M NaHCO3 extractable P (NaHCO3-Pi) as compared to higher soil moisture (=0.20). Depletion of P in soil solution in the immediate vicinity of root mats did not differ much but the extension of the depletion zones was 0.10 cm at =0.14 and 0.20 cm at =0.20. The depletion up to 0.05cm with =0.14 and up to 0.07 cm with =0.20 was uniform, and may be attributed to the depletion in the root hair zone. Beyond the root hair zones, the theory of diffusion and mass flow was able to explain the observed differences in shape and extent of the P depletion profiles at the two soil moisture levels. 相似文献