Incidence of parasites ofLymantria obfuscata [Lymantriidae: Lepidoptera] in Kashmir

Incidence of parasites ofLymantria obfuscata Walker [Lymantriidae: Lepidoptera] was studied in Kashmir during 1983 and 1984. The only egg parasite reared wasAnastatus kashmirensis Mathur parasitising between 4.49 to 11.92 percent of eggs. From 15 study sites as many as 10475 larvae of different stages and pupae were collected and reared in laboratory.Exorista rossica [Tachinidae: Diptera] was recorded to parasitize upto 8.42 per cent of larvae compared to 0.89 percent byCompsilura sp.Tetrastichus sp. [Eulophidae: Hymenoptera] was observed to be most dominant of the 6 pupal parasites, accounting for 33.41 percent of the measured parasitism, followed byPimpla sp. [Ichneumonidae: Hymenoptera] andTheronia atalantae atalantae [Ichneumonidae: Hymenoptera] which parasitized 6.84 and 4.03 per cent of pupae respectively.Brachymeria intermedia Nees [Chalcididae: Hymenoptera] was recorded to parasitize upto 2.98 per cent whereasBrachymeria lasus Walker recorded for the first time in Kashmir was found to parasitize up to 2.01 per cent, but was not widely distributed in the State.     

The genes for ribosomal RNA in diploid and polytene chromosomes of Drosophila melanogaster

The proportion of the Drosophila genome coding for ribosomal RNA was examined in DNA from both diploid and polytene tissues of Drosophila melanogaster by rRNA-DNA hybridization. Measurements were made on larvae with one, two, three and four nucleolus organizer regions per genome. In DNA from diploid tissues the percent rDNA (coding for 28S and 18S ribosomal DNA) was found to be in proportion to the number of nucleolus organizers present. The number of rRNA genes within a nucleolus organizer therefore does not vary in response to changes in the number of nucleolus organizers. On the other hand, in DNA from cells with polytene chromosomes the percent rDNA remained at a level of about 0.1% (two to six times lower than the diploid values), regardless of either the number of nucleolus organizers per genome or whether the nucleolus organizers were carried by the X or Y chromosomes. This independence of polytene rDNA content from the number of nucleolus organizers is presumably due to the autonomous polytenization of this region of the chromosome. When the rDNA content of DNA from whole flies is examined, both the rDNA additivity of the diploid cells and the rDNA independence of polytene cells will affect the results. This is a possible explanation for the relative rDNA increase known to occur in X0 flies, but probably not for the phenomenon of rDNA magnification. — In further studies on DNA from larval diploid tissues, the following findings were made: 1) the Ybb-chromosome carries no rDNA; 2) flies carrying four nucleolus organizers do not tend to lose rDNA, even after eleven generations, and 3) the nucleolus organizer on the wild type Y chromosome may have significantly less rDNA than does that on the corresponding X chromosome.     

Isolation and characterisation of immunoglobulins in the serum of precolostral piglets

The presence of actively synthetized immunoglobulin in the serum of newborn precolostral germfree piglets was confirmed. This immunoglobulin, being of IgG antigenic type, carries determinants of typical IgG heavy and light chains and has a sedimentation constant of 4S. The first antibodies formed in germfree piglets after immunization with sheep red blood cells are of macroglobulinemic (IgM) nature. They are followed by formation of more slowly sedimenting antibodies of the IgG type. No fast sedimenting antibodies of the IgG type were detected.     

NaturalMycoplasma arthritidis infection in mice

B6C3F₁ mice from a hybrid production colony frequently were serologically positive by enzyme-linked immunosorbent assay (ELISA) and consistently negative by culture forMycoplasma pulmonis. Subsequently, 162 mice were obtained and intensively studied using an expanded group of cultural procedures, ELISA, and histopathology. Lesions attributable to mycoplasma infection were not found, butMycoplasma arthritidis was isolated from 20 mice. TheM. pulmonis ELISA was positive (IgM, IgG, or both) in 113 mice. Selected sera were tested simultaneously in both theM. pulmonis ELISA and in an ELISA usingM. arthritidis antigen, and were found to be positive in both the IgM and IgG classes in both ELISAs. Thus, cross-reacting antibody was produced in mice naturally infected withM. arthritidis, confirming previous observations based on experimental infections. To our knowledge, this is the first report of naturalM. arthritidis infection in laboratory mice.     

Immune response in human subjects at high altitude

Levels of immunoglobulins were determined in persons exposed to high altitude. The individuals studied included high altitude natives, sea level residents at high altitude for 2 years, and recent arrivals at high altitude. Increased IgG and IgA levels were found in high altitude natives and sea level residents at high altitude for 2 years when compared with sea level residents. In recent arrivals marked increase of IgG and IgG levels and slight rise in IgM was seen. Recent arrivals who suffered from high altitude pulmonary oedema showed marked elevation of IgG, IgM, and IgA. Immunoglobulin responses to both primary and secondary TAB inoculation were of a higher magnitude and more sustained at high altitude than at sea level.     

Localization of rDNA in the chimpanzee (Pan troglodytes) chromosome complement

In situ hybridization was used to identify the sites of rDNA in the chromosome complement of the chimpanzee (Pan troglodytes). The rDNA was present in the satellite regions of chimpanzee chromosomes 14, 15, 17, 22 and 23. Four of these (14, 15, 22, 23) are homologous to human chromosomes carrying rDNA: 13, 14, 21 and 22.     

On the carrying behaviour of basic South American primates

InCallithrix, Saguinus, Aotus, andCallicebus other group members than the mother participate in infant care. Differences among these species are obvious in respect to the time of being off any caregiver, and in respect to the carrying position (Aotus andCallicebus). Alloparental care, a basic behaviour pattern in these species, has evolved from the parking behaviour of the prosimians. The infants are «parked» at other group members.     

The role of homoeologous group 1 chromosomes in the control of rRNA genes in wheat

The presence of rRNA genes on homoeologous chromosomes 1A, 1B, and 1D of hexaploid wheat was investigated by rRNA/DNA hybridization, using DNA purified from aneuploid and substitution line derivatives of the variety Chinese Spring. Doubling the number of 1B chromosomes increased the number of rRNA genes by 31–49% but deleting the 1B chromosomes decreased the number by only 15–23%. This suggests that changes may occur in rRNA gene multiplicity at other nucleolar organizer sites to partially compensate for a deficiency of rRNA genes. There was no unequivocal evidence of rRNA genes on Chinese Spring chromosome 1A or 1D, but other varieties were shown to have rRNA genes on chromosome 1A. These results are consistent with the cytological observations that chromosomes 1A and 1B but not 1D possess nucleolar organizers.     

Biological activity of 125iodine labelled globin mRNA in an Ehrlich ascites cell-free system

Globin mRNA was isolated from avian erythroblasts and labelled with ¹²⁵iodine to a specific activity of 4.5×10⁶ dpm μg^-1 mRNA. The labelling procedure was modified as compared to common techniques in order to protect the mRNA against degradation. When this RNA is translated in an Ehrlich ascites cell-free system globin chains are synthesized as is demonstrated by the analysis of the in vitro synthesized products. The biological activity of ¹²⁵iodine labelled mRNA has proven to be 30% of that of unlabelled mRNA.