Diversity measures in macroinvertebrate and zooplankton communities related to the trophic status of subtropical reservoirs: Contradictory or complementary responses?

Macroinvertebrate communities have been widely used as a tool for assessing the environmental quality of freshwater ecosystems, whereas zooplankton communities have been to some extent neglected. However, the importance of using different indicators to achieve a more comprehensive framework of assessment regarding water quality has been recognized. This study compared estimates of species richness (number of species) and the Shannon–Wiener index for data on macroinvertebrate and zooplankton communities in tropical reservoirs and related them to their trophic state. The trop+hic classification was obtained by applying the Carlson index (1977) modified by Toledo et al. (1983), and the index of the Brazilian Society of the Environmental Technology Agency. The comparative response of the different indicators was analyzed using a series of bivariate correlations (Draftsman’s plot). The results illustrate that diversity measures, namely species richness, responded differently when related to the trophic classification of reservoirs, depending on the community considered. The species richness of zooplankton was positively related to hypereutrophic conditions, due to the higher number of rotifer species, including tolerant generalist species and at the same time, as a result of the exclusion of species from other groups, whereas for macroinvertebrates, species richness was negatively related to hypereutrophic conditions. Melanoides tuberculatus, which exhibits a high tolerance and competitive ability under such conditions, was the dominant species in macroinvertebrate communities, which excluded endemic species and reduced local richness and diversity. The same indicators applied to the zooplankton and macroinvertebrate communities might therefore provide contradictory responses regarding ecological quality assessment in tropical reservoirs, which suggest that zooplankton should be taken into account among the biological quality elements considered in the ecological quality assessment, management, and restoration of water bodies.     

Studies on anti-folate antimalarials in east Africa

Chlorproguanil-dapsone (CD) appears to be a promising anti-folate combination (Amukoye et al., 1997) to substitute for pyrimethamine-sulfadoxine (PS), which has a long half-life and against which there is resistance in several Plasmodium falciparum populations including the highly endemic lowland area near Muheza, Tanzania (Trigg et al., 1997).     

Distribution of freshwater macroinvertebrates in streams with dams and associated reservoirs on a subtropical oceanic island off southern Japan

The conservation of endemic fauna in freshwater ecosystems is a topical issue on small oceanic islands. Because these endemics have limited distributions, they are more vulnerable to extinction. This study is the first to clarify the distribution of freshwater macroinvertebrates including endemic and alien species in streams with dams and associated reservoirs on the Ogasawara Islands in the northwestern Pacific Ocean. In 2007, we conducted a field survey in streams and reservoirs of the Yatsuse River system and collected 22 taxonomic groups from 13 stations. Hierarchal cluster analysis and non-metric multi-dimensional scaling (NMDS) were performed for the presence/absence data of the macroinvertebrates, and the results indicated that (1) most of endemic species were present in inlet streams of dam reservoirs, (2) these endemic species were absent in the bottom sediments of the reservoirs because of oxygen depletion and (3) dams may be barriers to the migration of some species of amphidromous crustaceans. Because human modifications, such as dams and associated reservoirs, on a small oceanic island can rapidly result in fragmentation or loss of freshwater habitats of endemic species, the remaining habitat of these species, such as headwater streams, must be protected and preserved to avoid species extinction.     

Infectious disease in the Pleistocene: Old friends or old foes?

The impact of endemic and epidemic disease on humans has traditionally been seen as a comparatively recent historical phenomenon associated with the Neolithisation of human groups, an increase in population size led by sedentarism, and increasing contact with domesticated animals as well as species occupying opportunistic symbiotic and ectosymbiotic relationships with humans. The orthodox approach is that Neolithisation created the conditions for increasing population size able to support a reservoir of infectious disease sufficient to act as selective pressure. This orthodoxy is the result of an overly simplistic reliance on skeletal data assuming that no skeletal lesions equated to a healthy individual, underpinned by the assumption that hunter-gatherer groups were inherently healthy while agricultural groups acted as infectious disease reservoirs. The work of van Blerkom, Am. J. Phys. Anthropol., vol. suppl 37 (2003), Wolfe et al., Nature, vol. 447 (2007) and Houldcroft and Underdown, Am. J. Phys. Anthropol., vol. 160, (2016) has changed this landscape by arguing that humans and pathogens have long been fellow travelers. The package of infectious diseases experienced by our ancient ancestors may not be as dissimilar to modern infectious diseases as was once believed. The importance of DNA, from ancient and modern sources, to the study of the antiquity of infectious disease, and its role as a selective pressure cannot be overstated. Here we consider evidence of ancient epidemic and endemic infectious diseases with inferences from modern and ancient human and hominin DNA, and from circulating and extinct pathogen genomes. We argue that the pandemics of the past are a vital tool to unlock the weapons needed to fight pandemics of the future.     

Passing the message on: inheritance of epigenetic traits

Epigenetic modifiers play an important role in genome organization, stability and the control of gene expression. Three research groups that are exploring the transfer of epigenetic information between generations have recently published papers. Mary Alleman et al. have shown that RNA-directed chromatin changes mediate paramutation in maize, and Minoo Rassoulzadegan et al. have demonstrated that RNA also plays a role in paramutation in mice. A new aspect of epigenetic regulation has been revealed by Jean Molinier et al. - they have demonstrated that the memory of exposure to stress is transferred through several generations.     

Live immunisation against Theileria parva: containing or spreading the disease?

Although a live vaccine against Theileria parva has been available for over 30 years, concerns that vaccine strains can become established in resident tick populations have impeded its uptake in endemic areas. Recently, Oura et al. have examined the persistence of vaccine strains in immunised cattle using polymorphic genomic markers. They confirm that elements of the vaccine establish a carrier state in vaccinated animals and present evidence that alleles associated with vaccine strains emerge in co-grazing non-vaccinated cattle. However, the epidemiological impact of these observations might be tempered by extensive recombination of co-ingested strains in the tick vector.     

Divergence time of porcine reproductive and respiratory syndrome virus subtypes

Porcine reproductive and respiratory syndrome virus (PRRSV) recently emerged in domestic pigs of Western Europe and North America. Although time of emergence was identical on the two continents, genetic composition was markedly different with a clear geographical subtype structure, indicating that subtypes diverged in separate reservoirs prior to emergence. Genetic analyses have shown that the most recent common ancestor (MRCA) of Western European isolates existed around 1980 and that these originate from Eastern European pigs. These findings are challenged by a study of Hanada et al. who place the MRCA of all PRRSV isolates around 1980 and find that no significant subtype divergence occurred before emergence. Here, I discuss problems of information content, methodology, and biological plausibility associated with this study. Using alternative methodology, I reanalyze the existing data and conclude that the MRCA of all PRRSV isolates existed around 1880, 100 years before the date estimated by Hanada et al.     

Qualitative analysis of an HIV transmission model.

In 1988, a multiple-group model for HIV transmission with preferred mixing was proposed by Jacquez and coworkers. In the present paper, the work done by Jacquez et al. is extended. It is shown that the stability modulus of the Jacobian matrix at the no-disease equilibrium is a threshold for this model. Furthermore, if the no-disease equilibrium is unstable, the number of infected individuals will remain above a certain positive level regardless of initial levels; that is, the disease will persist uniformly. The stability of the endemic equilibrium in the case of restricted mixing is also studied. A series of sufficient conditions for local and global asymptotic stability of the endemic equilibrium are stated.     

Need tension relief fast? Try caveolae

Caveolae are protein-driven membrane invaginations that regulate both the physical and chemical composition of the plasma membrane. Sinha et?al. (2011) now show that caveolae are membrane reservoirs that are used to rapidly buffer against changes in membrane tension.     

Footprints of SARS-CoV-2 genome diversity in Pakistan, 2020–2021

The rapid spread of SARS-CoV-2 has significantly impacted the worldwide health system. The SARS-CoV-2 currently bears a remarkably low genetic diversity even though it carries one of the largest RNA genomes among viruses (Rausch et al., 2020). However, the coronaviruses harbor the capability of undergoing recombination at a high rate which can lead to the emergence of novel viral derivatives (Rausch et al., 2020; Gribble et al., 2021). This in turn requires not only global surveillance of SARS-CoV-2 genome in various countries but also careful scrutiny in animal genomic reservoirs. Conventionally, RNA viruses evolve with a high mutation rate, however, the presence of ExoN ribonuclease in SARS-CoV-2 genome has made its case different from other viral species (Gribble et al., 2021). The variables of natural selection which potentially drift the SARS-CoV-2 evolutionary dynamics can be recorded by analyzing deposited sequence genomes for its fitness, transmissibility potential, and pathogenicity (Rouchka et al., 2020). This can potentially provide a way to draw a holistic picture at a national level, while simultaneously providing a comparative overview with worldwide sequences.     

Plant diversity and ecology on the Qinghai–Tibet Plateau

The Qinghai–Tibet Plateau (QTP) comprises a platform (sometimes called the Qinghai–Tibet Plateau sensu stricto), the Himalayas, and Hengduan Mountains (Liang et al.,2018; Mao et al.,2021). The latter two parts and adjacent highlands are also called the Pan-Himalaya. Numerous plants are distributed there with many endemic species, probably because of the high diverse landscapes created by continuous geological and climatic activities (Favre et al.,2015; Mao et al.,2021). As the well known biodiversity hotspot of the alpine plants in the world (Sun et al.,2017), many studies have been conducted on evolutionary origin and ecological adaptation of those species occurring in the QTP (e.g., Wen et al.,2014, 2019; Zhang et al.,2019). In the present special issue, we collected 15 related papers on this topic. Among them, two are invited reviews. Mao et al. (2021) provide a comprehensive review of evolutionary origin of species diversity on the QTP. Especially, they outlined major disputes and likely causes in this research topic, including circumscribing and naming the QTP, the QTP uplifts, dating of molecular phylogenetic trees, non-causal correlations between QTP uplifts and species diversification and the unified ice sheet. The authors also summarized genomic advancements related to high-altitude adaptation of both plants and animals. Tong et al. (2021) reviewed the reproductive strategies of animal-pollinated alpine plants on the QTP, involving pollination system, pollen limitation, self-pollination, and sexual system. In this region, 95.4% of animal-pollinated plants are pollinated by insects (i.e., bees, moths, butterflies, and flies) with only 4% by vertebrates (i.e., bats and birds). Self-pollination through self-compatibility shift from outcrossing has become an effective reproductive strategy to overcome pollen limitation in alpine plants. The other 13 research papers aimed to address origin and adaptation of alpine flora involving three major lines of evidence: genomics, ecology, and paleobotany. We hope that the collection of these papers will increase our understanding of the origin, speciation, and adaptation of alpine species on the QTP.     

Molecular systematics of four endemic Batrachospermaceae (Rhodophyta) species in China with multilocus data

Four endemic Batrachospermaceae species in China, Batrachospermum hongdongense Xie & Feng, Batrachospermum longipedicellatum Hua & Shi, Kumanoa curvata (Shi) Vis et al., and Kumanoa intorta (Jao) Entwisle et al., were analyzed with multilocus data in order to assess their phylogenetic placement. Multilocus molecular data from one nuclear gene (the ribosomal SSU), one chloroplast gene (rbcL), and two mitochondrial genes (COI and the cox2-3 spacer) as well as morphological studies were used to determine the phylogenetic relationships of these endemic species within the Batrachospermales. Batrachospermum hongdongense and B. longipedicellatum had previously been placed in Batrachospermum section Batrachospermum, but based on the data from this study they should be transferred into section Helminthoidea. Kumanoa curvata and K. intorta clearly belong to the newly established genus Kumanoa.     

New tools for genome modification in human embryonic stem cells

Two recent papers outline improvements in gene editing technology that may facilitate the analysis of signaling networks important for development. The systems developed by both Thyagarajan and coworkers (Thyagarajan et al., 2007) in Nature Biotechnology, and Lombardo and colleagues (Lombardo et al., 2007) in Stem Cells, have the potential to advance our understanding of human embryonic stem cells.     

Lack of Staphylococcal Enterotoxin Production among Strains of Staphylococcus aureus from Bovine Mastitis in Denmark

Staphylococcal enterotoxins (SE’s) are a group of small exoproteins produced by some strains of Staphylococcus aureus. The SE’s, designated A to E according to their antigenic specificities, are important causes of food poisoning worldwide. Milk and dairy products are frequently associated with S. aureus enter-otoxin food poisoning, and it is supposed that infected milk from mastitic animals constitute the main source of enterotoxigenic S. aureus of animal origin (Bryon 1983, Gilmour & Harvey 1990, Bergdoll 1989). Indeed, S. aureus is the most common cause of bovine mastitis worldwide, and if mastitis strains produce SE this makes up an enormous reservoir of potential enterotoxin producers. The production of SE by S. aureus isolated from bovine mastitis have been investigated in several countries (Matsunaga et al. 1993, Kenny et al. 1993, Olson et al 1970, Orden et al. 1992, Olsvik et al. 1981, Adekeye 1980, Garcia et al. 1980, Abbar 1986, Harvey & Gilmour 1985). Since no studies have been performed on the prevalence of enterotoxigenic strains of S. aureus isolated from bovine mastitis in Denmark, a well characterized collection of S. aureus (Aarestrup et al. 1995) was investigated with respect to this property.     

江南油杉和台湾油杉核型的比较研究

<正> 江南油杉(Keteleeria cyclolepis Flous)和台湾油杉(Keteleeria formcsana Hayata)均为松科(Pinaceae)油杉属的常绿乔木,我国的特产树种,前者分布于云南、贵州、广西、广东、湖南,江西等省区,后者分布于台湾。油杉属(keteleeria)的细胞学资料已有Sugihara和王伏雄分别报道过铁坚油杉(K.dayidiana Beissn.)和云南油杉(K.     

Anomalously low endemic goiter prevalence among Efe pygmies

The existence of endemic goiter, caused by iodine deficiency and the presence of a dietary goitrogen, has been noted in eastern Zaire by a number of authors (De Visscher et al.: Journal of Clinical Endocrinology and Metabolism 21:175-188, 1961; Delange et al.: Journal of Clinical Endocrinology and Metabolism 34:1059, 1972). In the Ituri Forest of Huate-Zaire, two distinct populations, the Efe (pygmy) and Lese (Bantu), live in association with each other and have similar diets. The goiter survey reported here documents differences in goiter prevalence and severity between the nomadic pygmy and village-living Bantu populations. While the Efe have an overall goiter prevalence of 9.4%, the Lese have a goiter prevalence of 42.9%. Furthermore, Efe women living in Lese villages and subsisting on a Lese diet have a prevalence of goiter similar to that of forest-living Efe women. Village-living individuals born of Efe mothers and Lese fathers have a prevalence of goiter greater than that of pure Efe but less than that of Lese. While our data cannot exclude dietary explanations for the difference in goiter prevalence between the Efe and Lese, they do support the hypothesis that the Efe possess an adaptation to an iodine-deficient environment that does not result in the development of goiters.     

Neurotransmission in the vestibular endorgans--glutamatergic transmission in the afferent synapses of hair cells.

In the sensory pathways the first synapse is that between hair cells and primary afferent neurons and its most likely neurotransmitter candidate has long been thought to be glutamate. A number of pharmacological and electrophysiological studies have lent credence to this theory (reviewed by Bledsoe et al. 1988, Bobbin 1979, Ehrenberger and Felix 1991, Puel et al. 1991; Puel 1995) as has recent neurochemical and immunocytochemical work (reviewed by Ottersen et al. 1998; Usami et al. 2000). These recent studies reveal that the afferent hair cell synapse resembles the central glutamate synapses in many ways. Of the proteins confirmed to be involved in signal transduction and transmitter metabolism at most central synapses, many are also seen in the afferent hair cell synapse, and have an analogous compartmentation. On the other hand, there are also important differences, especially those related to the molecular mechanisms that underlie transmitter release.     

Helminthiasis, bystander diseases and vaccines: analysis of interaction

Helminthiasis has assumed a new medical and veterinary significance following the recognition of its immunomodulatory consequences for the severity of bystander conditions and the efficacy of immunization against non-helminthic diseases of humans and livestock. Recent papers by Jackson et al. and Turner et al. have an important bearing on research in these areas. One of the implications of their work is that the parasitological criterion of egg-positivity versus egg-negativity is too simplistic to use in co-infection and related studies unless accompanied by immunological analysis.     

Epigenetic Variations in Plant Hybrids and Their Potential Roles in Heterosis

Heterosis,one of the most important biological phenomena,refers to the phenotypic superiority of a hybrid over its genetically diverse parents with respect to many traits such as biomass,growth rate and yield.Despite its successful application in breeding and agronomic production of many crop and animal varieties,the molecular basis of heterosis remains elusive.The classic genetic explanations for heterosis centered on three hypotheses:dominance (Davenport,1908;Bruce,1910;Keeble and Pellew,1910;Jones,1917),overdominance (East,1908;Shull,1908) and epistasis (Powers,1944;Yu et al.,1997).However,these hypotheses are largely conceptual and not connected to molecular principles,and are therefore insufficient to explain the molecular basis of heterosis (Birchler et al.,2003).Recently,many studies have explored the molecular mechanism of heterosis in plants at a genome-wide level.These studies suggest that global differential gene expression between hybrids and parental lines potentially contributes to heterosis in plants (e.g.,Swanson-Wagner et al.,2006;Zhang et al.,2008;Wei et al.,2009;Song et al.,2010).Research suggests that genetic components,including cis-acting elements and trans-acting factors,are critical regulators of differential gene expression in hybrids (Hochholdinger and Hoecker,2007;Springer and Stupar,2007;Zhang et al.,2008).However,other research indicates that epigenetic components,the regulators of chromatin states and genome activity,also have the potential to impact heterosis (e.g.,Ha et al.,2009;He et al.,2010;Groszmann et al.,2011;Barber et al.,2012;Chodavarapu et al.,2012;Greaves et al.,2012a;Shen et al.,2012).