Responses against antigens encoded by theH-3 histocompatibility locus: Antigens stimulating class I MHC- and class II MHC-restricted T cells are encoded by separate genes

The purpose of this work was to study the genetic basis of histocompatibility antigens encoded by the mouse minor histocompatibility (H) locusH-3. Both class I major histocompatibility complex (MHC)-restricted cytotoxic T lymphocytes (CTL) and class II MHC-restricted helper T cells (TH) specific for antigens encoded by genes within theH-3 locus were isolated and analyzed. Typing a number of mouse strains for expression of antigens recognized by these TH and CTL suggested that there was a different strain distribution pattern of expression of the antigens recognized by TH compared with those recognized by CTL. Separation of the genes whose products stimulate TH from those whose products stimulate CTL was suggested by: (1) analysis of the strain B10.FS(92NX)/Grf that has undergone recombination within theH-3 region; (2) genetic segregation studies of (B10.UW-H-3 ^b/Sn×C57BL/10Sn)F₂ mice; and (3) F₁ complementation studies in which CTL specific for products of the TH-defined gene(s) could not be detected, even in the absence of immune responses to products of the CTL-defined genes. Taken together, these data suggest that in addition to two genes (B2m andCd-1) within theH-3 region whose products typically stimulate class I MHC-restricted CTL, there is at least one additional gene whose product selectively stimulates class II MHC-restricted TH. This new gene is located telomeric from the CTL-defined genes and between the lociwe andun on chromosome 2. These data demonstrate a novel degree of complexity of theH-3 “locus” and suggest selective presentation of minor H gene products in the context of class I or class II MHC proteins.     

Additional mapping of mouse chromosome 2 genes

The purpose of this work was to elucidate the genetic fine structure of the central portion of mouse chromosome (Chr) 2. Seven Chr 2 congenic mouse strains [B10.PA(L)-pa we un a ^t , B10.PA(L)-pa A ^w , B10.PA(L)-we un a ^t , B10.PA(J)-pa a, B10.FS-we A ^w , B10.C-we A ^w , and B10.YBR-a] were produced. Breeding studies were carried out using strains B10.PA(L)-pa we un a ^t and B10.LP-H-13 ^b to accurately determine the recombination frequencies between marker genes pa and we (1.9%±0.3), we and un (8.8%±0.5), and un and a ^t (4.5%±0.4) of strain B10.PA(L)-pa we un a ^t . These strains and other Chr 2 congenic strains were typed for immunologically defined loci using monoclonal antibody (mAb) C23 reactive with the gene product of B2m ^b T-lymphocyte clone C1 reactive with the gene product of H-3 ^a and H-3 ^c , and lymphocyte clone H1.8 reactive with the gene product of Hd-1 ^a . B2m and H-3 typing located a recombinational event separating [pa B2m H-3] from we (the order of bracketed genes is not known). Hd-1 typing indicated that Hd-1 maps distal to [H-42, H-44] and proximal to un. The gene order [pa, B2m, H-3], we, [H-42, H-45], Hd-1, un, H-13, a ^t , with H-44 mapping centromeric to Hd-1, is indicated by the data. Address correspondence and offprint requests to: R. J. Graff.     

The Ontogeny of Vocal Sequences: Insights from a Newborn Wild Chimpanzee (Pan troglodytes schweinfurthii)

International Journal of Primatology - Observations of early vocal behaviours in non-human primates (hereafter primates) are important for direct comparisons between human and primate vocal...     

A covalently bound photoisomerizable agonist. Comparison with reversibly bound agonists at electrophorus electroplaques

After disulphide bonds are reduced with dithiothreitol, trans-3- (α-bromomethyl)-3’-[α- (trimethylammonium)methyl]azobenzene (trans-QBr) alkylates a sulfhydryl group on receptors. The membrane conductance induced by this “tethered agonist” shares many properties with that induced by reversible agonists. Equilibrium conductance increases as the membrane potential is made more negative; the voltage sensitivity resembles that seen with 50 [mu]M carbachol. Voltage- jump relaxations follow an exponential time-course; the rate constants are about twice as large as those seen with 50 μM carbachol and have the same voltage and temperature sensitivity. With reversible agonists, the rate of channel opening increases with the frequency of agonist-receptor collisions: with tethered trans-Qbr, this rate depends only on intramolecular events. In comparison to the conductance induced by reversible agonists, the QBr-induced conductance is at least 10-fold less sensitive to competitive blockade by tubocurarine and roughly as sensitive to “open-channel blockade” bu QX-222. Light-flash experiments with tethered QBr resemble those with the reversible photoisomerizable agonist, 3,3’,bis-[α-(trimethylammonium)methyl]azobenzene (Bis-Q): the conductance is increased by cis {arrow} trans photoisomerizations and decreased by trans {arrow} cis photoisomerizations. As with Bis-Q, ligh-flash relaxations have the same rate constant as voltage-jump relaxations. Receptors with tethered trans isomer. By comparing the agonist-induced conductance with the cis/tans ratio, we conclude that each channel’s activation is determined by the configuration of a single tethered QBr molecule. The QBr-induced conductance shows slow decreases (time constant, several hundred milliseconds), which can be partially reversed by flashes. The similarities suggest that the same rate-limiting step governs the opening and closing of channels for both reversible and tethered agonists. Therefore, this step is probably not the initial encounter between agonist and receptor molecules.     

Palatability and feeding preferences of Uresiphita maorialis (Lepidoptera: Crambidae) for three Sophora species

In a three-hour bioassay, we tested the palatability and feeding preferences of Uresiphita maorialis (kōwhai moth) for Sophora tetraptera, Sophora microphylla and Sophora prostrata. Palatability tests showed no differences among the Sophora species. Feeding preferences, on the other hand, showed that S. tetraptera and S. microphylla leaves are preferred over S. prostrata leaves. Our results support our field observations in Wellington city parks and gardens showing that S. tetraptera and S. microphylla plants frequently have higher densities of larvae than S. prostrata.     

Biodeterioration of Mayan buildings at uxmal and tulum,Mexico

Uxmal and Tulum are two important Mayan sites in the Yucatan peninsula. The buildings are mainly composed of limestone and grey/black discoloration is seen on exposed walls and copious greenish biofilms on inner walls. The principal microorganisms detected on interior walls at both Uxmal and Tulum were cyanobacteria; heterotrophic bacteria and filamentous fungi were also present. A dark‐pigmented mitosporic fungus and Bacillus cereus, both isolated from Uxmal, were shown to be acidogenic in laboratory cultures. Cyanobacteria belonging to rock‐degrading genera Synechocystis and Gloeocapsa were identified at both sites. Surface analysis previously showed that calcium ions were present in the biofilms on buildings at Uxmal and Tulum, suggesting the deposition of biosolubilized stone. Apart from their potential to degrade the substrate, the coccoid cyanobacteria supply organic nutrients for bacteria and fungi, which can produce organic acids, further increasing stone degradation.     

Increase in Serum Ca2+/Mg2+ Ratio Promotes Proliferation of Prostate Cancer Cells by Activating TRPM7 Channels

TRPM7 is a novel magnesium-nucleotide-regulated metal current (MagNuM) channel that is regulated by serum Mg²⁺ concentrations. Changes in Mg²⁺ concentration have been shown to alter cell proliferation in various cells; however, the mechanism and the ion channel(s) involved have not yet been identified. Here we demonstrate that TRPM7 is expressed in control and prostate cancer cells. Supplementation of intracellular Mg-ATP or addition of external 2-aminoethoxydiphenyl borate inhibited MagNuM currents. Furthermore, silencing of TRPM7 inhibited whereas overexpression of TRPM7 increased endogenous MagNuM currents, suggesting that these currents are dependent on TRPM7. Importantly, although an increase in the serum Ca²⁺/Mg²⁺ ratio facilitated Ca²⁺ influx in both control and prostate cancer cells, a significantly higher Ca²⁺ influx was observed in prostate cancer cells. TRPM7 expression was also increased in cancer cells, but its expression was not dependent on the Ca²⁺/Mg²⁺ ratio per se. Additionally, an increase in the extracellular Ca²⁺/Mg²⁺ ratio led to a significant increase in cell proliferation of prostate cancer cells when compared with control cells. Consistent with these results, age-matched prostate cancer patients also showed a subsequent increase in the Ca²⁺/Mg²⁺ ratio and TRPM7 expression. Altogether, we provide evidence that the TRPM7 channel has an important role in prostate cancer and have identified that the Ca²⁺/Mg²⁺ ratio could be essential for the initiation/progression of prostate cancer.     

The role of fish-poultry integration on fish growth performance,yields and economic benefits among smallholder farmers in sub-Saharan Africa,Tanzania

Aquaculture practices from sub-Saharan Africa are characterised by low production, owing to improper technology. Production can be increased through integrating fish farming with other existing on-farm activities, particularly livestock husbandry. We assessed the role of fish-poultry integration on all male Nile tilapia, Oreochromis niloticus growth performance, yields and economic benefits among smallholder farmers in sub-Saharan Africa, Tanzania. The study also compared phytoplankton species composition, abundance and biomass between the fish-poultry integration and non-integrated system. After 180 days of the experiment, all male O. niloticus cultured under fish-poultry integration exhibited significantly higher growth rates than those in the non-integrated system (p < 0.05). Gross fish yield (GFY), net fish yield (NFY) and net annual yields (NAY) obtained from fish-poultry integration were significantly higher than those from non-integrated system (p < 0.05). Partial enterprise budget analysis revealed that fish-poultry integration was more profitable than the non-integrated system. Moreover, fish-poultry integrated system produced significantly higher phytoplankton abundance and biomass than those from the non-integrated system. Results demonstrate that rural smallholder farmers can achieve higher growth rate, farm net yields and income by integrating all male O. niloticus with other on-farm activities than practising a stand-alone fish culture system.