Oceanitis abyssalis: A new species of deep-sea wood-digesting Fungus from the Northwest Pacific abyssal plain.

The abyssal seafloor is an extreme environment, where organisms have to cope with high pressures, low oxygen and nutrient levels, permanent darkness, and low temperatures (with islands of extremely high temperatures around hydrothermal vents). Despite these obstacles, these deep-sea environments are home to a surprising range of organisms, including a number of Fungi which specialize in the decomposition of wood, a material of terrestrial origin. Do date only six species of obligate deepsea Fungi (i.e. Fungi found only in deep-sea environments) have been described, Alisea longicolla, Allescheriella bathygena, Bathyascus vermisporus, Oceanitis scuticella, Periconia abyssa, and Abyssomyces hydrozoicus, of which all except Abyssomyces hydrozoicus are wood-digesting species.

In a paper published in the journal Phytotaxa on 27 August 2024, Yukiro Nagano of the Marine Biodiversity and Environmental Assessment Research Center of the Japan Agency for Marine-Earth Science and Technology, and the Advanced Institute for Marine Ecosystem Change, Mohamed Adbul-Wahab of the Department of Botany and Microbiology at Sohag University, Ryota Nakajima, also of the Marine Biodiversity and Environmental Assessment Research Center of the Japan Agency for Marine-Earth Science and Technology, and Akinori Yabuki, also of the Advanced Institute for Marine Ecosystem Change, describe a new species of deep-sea wood-digesting Fungus from the Northwest Pacific abyssal plain.

The new species is placed in the genus Oceanitis on the basis of a genetic analysis, and given the specific name abyssalis in reference to the environment in which it was found, the abyssal plain of the Northwest  Pacific close to the Kuroshio Extension current boundary. The species is described on the basis of a colony found growing on a branch of wood with bark still attached, from a depth of 5707 m.

Oceanitis abyssalis (TNS-F-70722, holotype): Ascomata on wood. Nagano et al. (2024).

Oceanitis abyssalis produces fleshy yellowish or brownish ascomycota (spore-producing bodies) on the surface of the wood, which are yellowish in colour, 1.2-1.6 mm high and 0.98-1.2 mm in diameter. It is very similar, both morphologically and genetically, to samples of Oceanitis scuticella collected from the Kuril-Kamchatka Trench, but is morphologically different from the original description of Oceanitis scuticella, which was based upon material from bathyal depths near the islands of Vanuatu, which was not genetically analysed, and is no longer available (to date, no deep-sea Fungus has been cultured in the lab). For this reason, Nagano et al. question whether the Kuril-Kamchatka Trench Oceanitis scuticella material should be placed in this species, suggesting that Oceanitis cf abyssalis might be a better designation for the time being.  

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Neotropicomus indicus: A 'South American' Mushroom from India.

The genus Neotropicomus was created in 2022 to include two species of Boletacean Mushrooms from South America, the previously described Xerocomus parvogracili (which became Neotropicomus parvogracili) from Guyana, and a new species, Neotropicomus australis, from the Atlantic Forests of Brazil. The name 'Neotropicomus' refers to the Neotropical Realm, the biological zone which incorporates the tropical biomes of South and Central America and the Caribbean islands, to which region the new genus was thought to be restricted.

In a paper published in the journal Cryptogamie Mycologie on 27 March 2024, Salna Nanu and Arun Kumar of the Department of Botany at the University of Calicut, describe a third species of Neotropicomus from Kerala State in India.

The new species is named Neotropicomus indicus, in reference to its unexpected presence in India. It produces small Mushrooms 20-30 mm across, which are convex when young, but flatten out as they age. The upper surfaces of the Mushrooms are reddish brown, fading to greyish towards the centre. The gills and stipe (stem) are white, with the stipe being 20-40 mm long and 3-4 mm wide.

Neotropicomus indicus, holotype, basidiomata. Nanu & Kumar (2024).

Neotropicomus indicus Mushrooms were found growing solitary in Diptocarp forests in Thiruvananthapuram District. It physically resembles other members of the genus Neotropicomus, and was confirmed as being the sister taxon to the other members of the genus by a genetic analysis.

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Zygosporium himachalensis: A fossil Ascomycote Fungus from the Miocene of Himachal Pradesh, India.

The genus Zygosporium contains asexual, largely saprotrophic, Ascomycete Fungi distinguished by dark brown setiform conidiophores (bristle-shaped spore producing bodies) with darkly pigmented, incurved, and swollen vesicles, often stacked, emerging either from the side of the conidiophore or from the mycelium (network of fungal threads).There are 22 described living species within the group, as well as three known fossil species, two from the Siwalik sediments of the eastern Himalayas, and one from the Oligocene of Hungary.

In a paper published in the journal Fungal Biology on 12 March 2023, Sampa Kundu and Mahasin Ali Khan of the Palaeobotany and Palynology Laboratory at the Department of Botany at Sidho-Kanho-Birsha University, describe a new species of Zygosporium from the Late Miocene Middle Siwalik of Himachal Pradesh, in the western Himalayas.

The new species is named Zygosporium himachalensis, where 'himachalensis' means 'from Himachal'. It is based upon a series of specimens found growing on a compressed Monocot leaf recovered from a grey mudstone in the Middle Siwalik in Mandi District of Himachal Pradesh. This location is about 8-10 km from, and probably coeval with Nalad Khad Section, which has been dated to 12-8 million years before the present.

(A) A compressed Monocot leaf segment; (B) Light microscopic image of Zygosporium himachalensis (SKBUH/PPL/HP/M40/S2) showing superficial or partly immersed hyphae with vesicular conidiophores in small or large groups or scattered on fossil Monocot leaf cuticle (SKBUH/PPL/HP/M40); (C), (D), (E), (G). Zygosporium himachalensis showing stacked chained vesicular cells on straight erect unbranched conidiophores; vesicular cells arising from apical, sub-apical, and lateral sides of the conidiophores (vesicular cells marked by blue arrows); (F) Zygosporium himachalensis showing stacked chained vesicular cells on a branched conidiophore (branching point marked by a black arrow; vesicular cells marked by blue arrows). Kundu & Khan (2024).

Specimens of Zygosporium himachalensis have erect, usually unbranched conidiophores, with chains of up to 4 integrated alternatively or suboppositely arranged vesicles arising directly from the mycelium. These are arranged in effuse or sometimes compact irregular-shaped patches on the surface of the leaf.

(A)–(L) Light microscopic images of Zygosporium himachalensis showing septate superficial conidiophore (marked by white arrows) with alternately (marked by blue arrows) and sub-oppositely (marked by green arrow) arranged dark brown to black, swollen, incurved, thick-walled vesicular cells (marked by red arrows); some vesicular cells with a cylindrical, brown, thick-walled, smooth, short stalk cell (marked by black arrows). Kunda & Khan (2024).

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Talaromyces sedimenticola: A new species of Ascomycote Fungus from the deepest part of the Mariana Trench.

The Challenger Deep forms the deepest part of the Mariana Trench, reaching 10 971 m below sealevel. Curiously, recent studies have shown that the hadal depths of the oceans (areas more than 6 km deep) have a higher microbial carbon turnover than occurs at abyssal depths, between 4 km and 6 km below the surface. This has been supported by metagenomic studies which have shown significantly more genes coding for carbohydrate-active enzymes and peptidase are being expressed at these depths. This has led microbiologists to take an interest in the organisms living in the sediments of the deepest ocean trenches. 

In a paper published in the journal Antonie van Leeuwenhoek on 28 February 2024, Hongbo Zhou of the School of Minerals Processing and Bioengineering and the Key Laboratory of Biometallurgy at Central South University, Liting Xu and Wenxian Liu, also of the School of Minerals Processing and Bioengineering at Central South University, Kaiwen Ta of the Institute of Deep-Sea Science and Engineering of the Chinese Academy of Sciences, Xincun Wang of the State Key Laboratory of Mycology at the Institute of Microbiology of the Chinese Academy of Sciences, Jianwei Guo of the College of Agronomy and Life Sciences at Kunming University, Wenxi Luo, Zhiyuan Peng, and Qiaoni Huang, again of the School of Minerals Processing and Bioengineering at Central South University, and Yuguang Wang, once again of the School of Minerals Processing and Bioengineering and the Key Laboratory of Biometallurgy at Central South University, describe a new species of Ascomycote Fungi from the Challenger Deep.

The new species is described on the basis of two strains isolated from samples collected by the Research Vessel Tan Suo Yi Hao in September 2019, from a depth of 10 063 m below sealevel. A genetic analysis of these strains suggests that they belong to the same species, and, surprisingly, that that species  is a member of the genus Talaromyces, which mostly comprises terrestrial moulds, forming a sister taxon to a clade which includes Talaromyces trachyspermus, which is a serious commercial pest species, frequently infecting packaged fruit juices, and Talaromyces assiutensis, which is found growing within the leaves of Mangroves around the South China Sea. The new species is named Talaromyces sedimenticola, in reference to the environment where it was found.

Morphological characteristics of Talaromyces sedimenticola, (k), (l) conidiophores, (m) conidia. Zhou et al. (2024).

While morphologically similar, and genetically close, to other members of the genus Talaromyces, Talaromyces sedimenticola shows some remarkable physiological traits, which mark it out as distinctive. It could be grown at temperatures of between 4°C and 50°C, unlike most Talaromyces species, which typically grow between about 28°C and 40°C. It could also survive and grow over a far wider pH range than any other species within the genus, pH 1.5-12, whereas other Talaromyces species could only survive in the pH range 4-8, with the exception of Talaromyces aculeatus, a widespread soil-dwelling form, which can survive over the range pH 1-7. Talaromyces sedimenticola is also remarkably halotollerant, able to flourish on media with 0-14% sodium chloride (weight over volume). More curiously, Talaromyces sedimenticola was unable to metabolise sucrose, tryptone, or monobasic potassium phosphate, all of which can be utilised by other members of the genus, although it was able to utilise other common foodstuffs, such as glucose, maltose, lactose, xylose, soluble starch, glycerol, peptone, ammonium sulphate, potassium phosphate, potassium chloride, and magnesium sulphate. 

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Tuber itzcuinzapotl: A new species of edible Truffle from Mexico.

Truffles, Tuber spp., are Ascomycote Fungi which from ectomycorrhizal relationships with a range of forest Plants, including Pines, Oaks, Hickories, and Orchids. They are distinguished for their large, tuber-like ascomata (fruiting bodies), which are formed underground, which often have highly distinctive aromas and flavours, leading to some species being traded as high-value gourmet items.

There are currently 25 species of Truffle known from Mexico, mostly from the temperate forests of the north and the mountains of the Neovolcanic axis. However, none of these are currently traded as foodstuffs, despite Mexico a globally leading countries in terms of the number of edible wild Fungi consumed, with about 500 species, making it second only China, where about 1000 are consumed. However, recent efforts have found that the non-native Black Truffle, Tuber melanosporum, will form ectomycorrhizal relationships with native Mexican Oaks, and several species found in Mexico are considered to have potential for commercial development, including the Pecan Truffle, Tuber lyonii, which is commercially exploited in the US and Canada, and can trade for up to US$400 per kg.

In a paper published in the journal Phytotaxa on 26 January 2024, Javier Isaac de la Fuente of the Colegio de Postgraduados at Campus Montecillo, Wendy Rosales-Rosales of the Instituto Tecnológico Superior de Zongolica of the Tecnológico Nacional de México, César Romero Martínez-González of the Instituto Tecnológico de Ciudad Victoria of the Tecnológico Nacional de México, Magdelana Martínez-Reyes, also of the Colegio de Postgraduados at Campus Montecillo, Andrea Carolina Elizondo-Salas, also of the Instituto Tecnológico Superior de Zongolica of the Tecnológico Nacional de México, and Jesús Pérez-Moreno, agian of the Colegio de Postgraduados at Campus Montecillo, describe a new species of edible Truffle from the Coniferous mixed forests of eastern Mexico.

The new species is named Tuber itzcuinzapotl, where 'itzcuinzapotl' means 'Dog's Zapote' in the Nahua language (a Zapote is a type of fruit). This Truffle produces subglobose fruiting bodies with a light brown, verrucous-granular outer surface, and an gray or pale brown interior, reaching up to 28 mm by 28 mm in size, with a distinctive fruity taste and smell. It is found growing in association with Mexcan Weeping Pines, Pinus patula, in Veracruz State, Mexico.

Tuber itzcuinzapotl (Holotype). Fresh ascomata fruiting body. De la Fuente et al. (2024).

Mexico has a significant culture of wild Fungus consumption, with over 500 types of Fungi consumed by members of all ethnic groups, and in particular rural communities living close to woodland. However, almost all consumed Fungi are epigeal, i.e, found above the ground, such as Mushrooms, with very little exploitation of subterranean species occurring. This is surprising, as Mexico is one of the most biodiverse regions in the world for Oaks, and Oaks are particularly associated with Fungi producing underground fruiting bodies. 

Tuber itzcuinzapotl is known to be consumed by members of the Nahua ethnic group living in the Sierra de Zongolica region of Veracruz State, Mexico, where it is referred to as 'itzcuinzapotl' (the specific name chosen for the species). Local folklore has it that people began to consume these Fungi after observing Dogs digging them up and eating them. Knowledge of the Fungus appeared to be restricted to older women in the community. Such local knowledge of wild foodstuffs is considered to be at risk in the region as traditional cultures are eroded, leading to loss of knowledge and a reduction and homogenisation in the number of foodstuffs consumed by Humans both in Mexico and globaly.

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Fungal Meningitis infections reported at two Mexican hospitals.

On 11 May 2023, the United States of America Centers for Disease Control and Prevention notified the Mexico General Directorate of Epidemiology of five cases with central nervous system infection in the United States of America, according to a press release issued by the World Health Organization on 1 June 2023.. All five cases were females with a history of undergoing surgical procedures performed under spinal anaesthesia in Mexico. The surgeries were performed in two private clinics, located in the city of Matamoros in Tamaulipas State, on the border with the USA.  Laboratory test results from samples collected from patients in the USA and Mexico were consistent with Meningitis caused by pathogenic Fungi. Fungal Meningitis is rare but can be fatal and requires immediate medical care. 

As of 26 May 2023, the health authorities from Mexico and the USA have reported a total of 20 cases presenting with signs and symptoms compatible with central nervous system infection, including two deaths reported by the United States of America Centers for Disease Control and Prevention. Patients presented to the hospital with symptoms including headache, fever, nausea, vomiting, sensitivity to light, and fainting after receiving surgical procedures in two private clinics in Mexico, between January and April 2023.

The Mexico Epidemiological Diagnosis and Reference Institute has received five samples of cerebrospinal fluid that tested positive for a Fungus, Fusarium solani by real-time polymerase chain reaction. Additionally, according to the health authorities from the USA, the laboratory results from nine suspected cases were consistent with Meningitis, of which two cerebrospinal fluid and two blood samples showed elevated levels of (1,3)-beta-D-glucan, a biomarker for Fungal infection.  Two pan-fungal polymerase chain reaction tests were negative.

Fusarium solani is a common, filamentous Acomycote Fungi, found in soil systems worldwide, but known to occasionally cause opportunistic infections, typically of the eyes. Although distinct from other members of the genus Fusarium, Fusarium solani is now recognised to be a species complex, i.e. a group of closely related and morphologically similar species, which are nonetheless genetically isolated from each other. 

Hyphae of Fusarium solani stained with Prussian blue. Josef Reischig/Wikimedia Commons.

According to the investigation performed, a total of 547 people had these procedures  between January and April 2023 in the concerned two private clinics, of whom 304 (56%) reside in Mexico, 237 (43%) in the United States, and one in Canada.

Several species of Bacteria, Viruses, Fungi, and Parasites can cause Meningitis, an inflammation of the tissues surrounding the brain and spinal cord. Fungal Meningitis can develop after a Fungal infection spread from somewhere else in the body to the central nervous system. It can be fatal and requires immediate medical care.  While rare, medical and surgical procedures can lead to Fungal Meningitis if medical devices or medications are contaminated with Fungi, or if proper infection prevention control practices are not taken. This type of healthcare-associated infection can lead to severe illness or death. Healthcare-associated Fungal Meningitis outbreaks have occurred among patients who received spinal anesthesia.

Fungal Meningitis cases following a medical/surgical procedure are very infrequent and unusual. In 2012, the United States of America Centers for Disease Control and Prevention investigated a multistate outbreak of Fungal Meningitis and other infections among patients who received contaminated preservative-free methylprednisolone acetate steroid injections; 753 cases were reported, including 64 deaths in 20 States in the USA.

The source, vehicle, and the transmission route for the current outbreak remains unknown, although the investigations are ongoing. A Fungal infection is suspected based on preliminary information provided by the health authorities from Mexico and the USA.

Each year, more than a million people from the USA participate in medical tourism. In 2017, more than 1.4 million Americans sought health care in a variety of countries around the world. These medical tourists commonly travel to Mexico, Canada, and countries in Central America, South America, and the Caribbean. At present, there is no evidence to suggest any secondary spread from these cases of health care associated Fungal Meningitis The involved healthcare facilities where the procedures were undertaken have been closed since 13 May. However, there is an ongoing investigation and follow up of people who may have been exposed to Fungal infections. This may lead to additional cases being reported until the follow up of people exposed to such procedure is completed.

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